Analytics
2/4/2014
08:04 AM
Tim Wilson
Tim Wilson
Quick Hits
50%
50%

GameOver Zeus Authors Try A New Tactic: Encryption

Authors of malicious GameOver Zeus exploit dodge detection with new encryption scheme

The authors of the GameOver Zeus malware are taking a new approach to avoiding detection: encryption.

According to a blog posted Sunday by researchers at Malcovery Security, the new approach could enable the malware to escape conventional security defenses.

Gary Warner, co-founder and CTO at Malcovery, writes that GameOver Zeus' authors are "encrypting their EXE file so that as it passes through your firewall, Web filters, network intrusion detection systems, and any other defenses you may have in place, it is doing so as a non-executable '.ENC' file."

While antivirus tools and other products have recently improved their ability to detect and block the dangerous Zeus variant, the encrypted attack was not detected by any of the 50 products used by VirusTotal, according to the blog.

"Why? Well, because technically, [the encrypted ENC file] isn't malware," Warner writes. "It doesn't actually execute! All Windows EXE files start with the bytes 'MZ.' These files start with 'ZZP.' They aren't executable, so how could they be malware? Except they are."

In the blog, Warner gives many examples that show how the campaign works and how the malware is delivered. He also offers a bit of advice.

"If you are in charge of network security for your enterprise, you may want to check your logs to see how many .ENC files have been downloaded recently," the blog warns.

Have a comment on this story? Please click "Add a Comment" below. If you'd like to contact Dark Reading's editors directly, send us a message. Tim Wilson is Editor in Chief and co-founder of Dark Reading.com, UBM Tech's online community for information security professionals. He is responsible for managing the site, assigning and editing content, and writing breaking news stories. Wilson has been recognized as one ... View Full Bio

Comment  | 
Print  | 
More Insights
Register for Dark Reading Newsletters
White Papers
Cartoon
Current Issue
Flash Poll
Threat Intel Today
Threat Intel Today
The 397 respondents to our new survey buy into using intel to stay ahead of attackers: 85% say threat intelligence plays some role in their IT security strategies, and many of them subscribe to two or more third-party feeds; 10% leverage five or more.
Video
Slideshows
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2015-4231
Published: 2015-07-03
The Python interpreter in Cisco NX-OS 6.2(8a) on Nexus 7000 devices allows local users to bypass intended access restrictions and delete an arbitrary VDC's files by leveraging administrative privileges in one VDC, aka Bug ID CSCur08416.

CVE-2015-4232
Published: 2015-07-03
Cisco NX-OS 6.2(10) on Nexus and MDS 9000 devices allows local users to execute arbitrary OS commands by entering crafted tar parameters in the CLI, aka Bug ID CSCus44856.

CVE-2015-4234
Published: 2015-07-03
Cisco NX-OS 6.0(2) and 6.2(2) on Nexus devices has an improper OS configuration, which allows local users to obtain root access via unspecified input to the Python interpreter, aka Bug IDs CSCun02887, CSCur00115, and CSCur00127.

CVE-2015-4237
Published: 2015-07-03
The CLI parser in Cisco NX-OS 4.1(2)E1(1), 6.2(11b), 6.2(12), 7.2(0)ZZ(99.1), 7.2(0)ZZ(99.3), and 9.1(1)SV1(3.1.8) on Nexus devices allows local users to execute arbitrary OS commands via crafted characters in a filename, aka Bug IDs CSCuv08491, CSCuv08443, CSCuv08480, CSCuv08448, CSCuu99291, CSCuv0...

CVE-2015-4239
Published: 2015-07-03
Cisco Adaptive Security Appliance (ASA) Software 9.3(2.243) and 100.13(0.21) allows remote attackers to cause a denial of service (device reload) by sending crafted OSPFv2 packets on the local network, aka Bug ID CSCus84220.

Dark Reading Radio
Archived Dark Reading Radio
Marc Spitler, co-author of the Verizon DBIR will share some of the lesser-known but most intriguing tidbits from the massive report