Ramnit Malware Makes a Comeback via Google Play

Ramnit Malware Makes a Comeback via Google Play

Ramnit, the once notorious malware that infected 3.2 million computers around the world, has resurfaced via infected apps on Google Play.

Symantec researchers found 92 distinct apps on Google Play with a total of 250,000 downloads laden with Ramnit malware. Some of the Ramnit-infected apps that turned up on Google Play were educational and tutorial apps.

Symantec informed Google of the presence of these infected apps and the company has removed them from the app store. This isn’t the first time that Ramnit-infected apps have turned up on Google Play. In March of this year, more than 100 Ramnit-infected apps were similarly removed from Google Play.

Ramnit first appeared in the wild in 2010. In February 2015, a law enforcement operation led by the European Union Agency for Law Enforcement Cooperation (Europol) crippled the operation of the cybercrime group behind Ramnit by shutting down the command and control servers, as well as shutting down and 300 internet domain addresses used by the group. At the time, the group already infected 3.2 million computers in total and defrauding undetermined large number of victims.

The law enforcement operation against the group behind Ramnit was participated by investigators from Germany, Italy, the Netherlands and the UK. Representatives from the private industry like Symantec and Microsoft were also involved in the law enforcement operation.

Ramnit Features

Ramnit is a multi-feature cybercrime tool. It compromised a victim in the following manner:

Spy Tool

This malware monitors web browsing activities and detects when certain websites like online banking sites are visited. Ramnit can inject itself into the web browser and alter the website of the bank to make it appear that the bank is asking the user additional information like credit card details.

Cookie Grabber

This malware can hijack online banking sessions. Ramnit attackers achieve this by stealing session cookies from web browsers and by using the stolen cookies to impersonate victims to authenticate themselves on websites.

Drive Scanner

This malware scans computer’s hard drive. It’s configured in such a way to search for specific folders that are considered likely to contain sensitive information like passwords.

Remote Access

This malware can gain remote access – upload, download, or delete files and execute commands – on the victim’s computer in two ways: by connecting to an anonymous FTP server and by Virtual network computing (VNC) module.

Persistent Threat

Ramnit is a persistent cyber threat. The malware’s creators made sure that once a computer is infected it’ll be difficult to remove the malware from the compromised computer.

Once the malware is installed on the compromised computer, it copies itself to the computer’s memory, hard drive and removable drive. The malware’s version that’s copied to the computer’s memory checks the hard disk-based copy of the malware. If the memory-based copy of the malware detects that the hard disk-based copy has been quarantined or removed, it’ll create another malware copy for the hard disk to sustain the infection.

Microsoft describes Ramnit malware this way: "This malware family steals your sensitive information, such as your bank user names and passwords. It can also give a malicious hacker access and control of your PC, and stop your security software from running."

How Ramnit Spreads

While the latest method of propagation of Ramnit is via Android apps, this doesn’t, however, mean that this malware works with Android devices. Since its appearance in 2010, this malware has always been a threat to computers using Windows as an operating system.

Ramnit won’t run on your Android device even if you’ve the misfortune of downloading a Ramnit-infected app on Google Play. In order for the Windows infection to happen, an Android device loaded with a Ramnit-infected app has to be connected to a Windows computer. Once the malware compromised a Windows computer, it searches for all exe, .dll, .htm, and .html files on any removable drives like USB drive and the local hard disk and infects them by making copies of itself.

“The HTML file infection process uses two tactics: injecting VBScript code into an HTML page that drops and executes the worm, and also injecting a hidden iframe into HTML files that downloads a remote file if the page is opened in a browser,” Symantec said.

Ramnit malware is one of the reasons why it’s unsafe to use or borrow removable drive or USB flash drive of another. You never know, this USB drive may be laden with the Ramnit malware.

In addition to propagating the malware through infected apps and through infected removable drives, Ramnit attackers also spread the malware through malicious emails and exploit kits served through malicious advertisements on social media pages and websites. Public FTP servers are also used by Ramnit attackers to distribute the malware. The Europol considers Ramnit as a botnet.

“This botnet – a term used to describe a network of infected computers - was used by the criminals running it to gain remote access and control of the infected computers, enabling them to steal personal and banking information, namely passwords, and disable antivirus protection,” Europol said. “This malware, infecting users running Windows operating systems, explored different infection vectors such as links contained in spam emails or by visiting infected websites.”

"Despite the setback many years ago, Ramnit’s operators have not completely gone away and there also seem to be many latent infections worldwide,” Symantec said. “We know that Google has a system in place for vetting uploaded apps, but we don’t have visibility into the processes for vetting submitted apps, so we can’t say for sure why these infected apps are getting through the vetting process.”

How to Prevent Ramnit Attacks

According to Microsoft, Windows Defender Antivirus detects and removes Ramnit malware.

Here are additional tips for preventing Ramnit attacks:

1. Keep your operating system and all software up-to-date.
2. Only install apps from trusted sources.
3. Carefully scrutinize the permissions requested by an app.
4. Exercise caution with emails and websites. Think before you click anything.
5. Backup your data.