Malwarebytes uncovers AV-dodging ransomware in Java exploit kit

Security firm Malwarebytes has discovered new ransomware being spread by the Neutrino exploit kit, targeting Java with a fake Skype file.

Malwarebytes security researchers Jerome Segura and Joshua Cannell reported discovering Neutrino on Monday, warning the ransomware can bypass all major antivirus products.

"Malwarebytes identified a ransomware Trojan, part of the Urausy family, which was being spread by a new Exploit Kit dubbed Neutrino. This ransomware sample evaded AV detection for almost a day and uses several levels of encryption to hide its payload," Segura told V3.

"The Exploit Kit itself was discovered in the wild by security researcher
Kafeine and it uses two recent Java vulnerabilities and a trick to bypass
the security warnings to execute silently."

The exploit kit is designed to target security flaws in Oracle's Java version 7 update 11 platform.

"In plain English, malicious applets can run without any warnings or user interaction. Following exploitation, a malware binary is downloaded by the Java process," explained Cannell.

"This practice is becoming more and more common these days as it makes detection by looking at traffic packets more difficult.

"The file is swiftly decrypted by the Java applet which in turns launches it. Upon execution the binary connects to a remote server and downloads the ransomware interface directly onto the victim's machine."

Ransomware typically locks a user's machine and then demands that the user pays for access to be restored.

Numerous forms of the malware have been spotted in the wild masquerading as messages from legitimate companies and law enforcement agencies.

The Neutrino attack pretends to be a legitimate Skype file to gain access to a user's machine.

"Analysis reveals the ransomware binary to be a skype.dat variant that's commonly seen in the wild. It's called this because the ransomware renames itself to "skype.dat" and is placed in the folder, along with a configuration file called "skype.ini," said Cannell.

"The skype.dat ransomware has nothing to do with the legitimate Skype program that millions of people use for VoIP communication."

The exploit kit's discovery comes amid widespread warnings within the security community that criminal's use of ransomware is growing.

At the end of 2012 security firm Symantec issued a report suggesting ransomware scams are now earning criminals as much as $33,000 a day.

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• Topics
• Security
• Hacking
• malware
• cyber-crime
• Java
• Skype