Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Attacks/Breaches

Modular Malware Brings Stealthy Attacks to Former Soviet States

A new malware technique is making phishing attacks harder to spot when they succeed.

Modular downloaders aren't new to the world of malware, but a new campaign featuring modular software launched by a major criminal group is drawing the attention of threat researchers. The attacks, so far targeting Russia and the former Soviet republics of the Commonwealth of Independent States (CIS), could presage new tactics aimed at victims around the world.

Researchers at Proofpoint discovered a pair of modular downloaders this summer and noticed two unusual factors in their use. First, the loaders were conducting reconnaissance on the infected system to decide whether the full payload will be downloaded. Second, the loaders, with very small and carefully obfuscated footprints, were being launched by the Cobalt Group, a major criminal organization previously tied to activities such as ATM jackpotting and to other large criminal groups.

"This is the first time we've seen a real shift to have a number of major actors using these tiny downloaders," says Chris Dawson, threat intelligence lead at Proofpoint. The new modular downloader — dubbed "CobInt" by researchers at Group-IB for the organization launching the attack and the name of a .DLL used in the malware — is "small, it's stealthy, and it's pretty well-obfuscated," he adds. "It's difficult to detect if you don't know what you're looking for."  

The process of infecting a target machine is a three-step flow, with each step adding functionality, Dawson explains. The first module is an email with an attachment carrying the initial exploit. If the exploit code, typically a .VBS exploit, can execute, it immediately sends a request for the second-stage downloader. This downloader, written in C, will do reconnaissance on the target system to determine whether certain security measures are running, the system is within a sandbox, or has qualities indicating that it might trap the malware. If the system is "clean" (from the malware's perspective), then it downloads the final payload and establishes persistence on the computer.

Each of the three modules is small and uses multiple layers of obfuscation to avoid detection. "It's unusual to see this level of obfuscation, and we've seen it three times in a row by high-profile actors," says Dawson, referring to separate campaigns researchers have found using the same modular software in the space of a few weeks.

And while the process has multiple steps, it doesn't mean that security professionals can look for the malware at their leisure. "The total time is seconds — it's very quick," Dawson says.

So far, the specific code in use is particular to one criminal organization, and Dawson thinks it will stay that way. "This is likely going to remain a Cobalt Group tool. Aside from using Cobalt Strike, which is a readily available tool, they use custom software," he explains.

But in the world of criminal IT activity, the Cobalt Group's success will be noticed. "We've seen these techniques spreading through other groups," Dawson says. "We see a group that tends to be a good barometer using the technique, and if TA505 is using this, it indicates that others with follow in their wake."

Asked whether he sees these campaigns spreading outside the CIS states, Dawson points out that they are, so far, very specific. "In general, it's Russian language [phishing] hitting organizations in the region," he says. But there's no technical reason that another group can't adopt the technique — if not the actual code — for use anywhere in the world.

Related content:

 

 

Black Hat Europe returns to London Dec 3-6 2018  with hands-on technical Trainings, cutting-edge Briefings, Arsenal open-source tool demonstrations, top-tier security solutions and service providers in the Business Hall. Click for information on the conference and to register.

Curtis Franklin Jr. is Senior Editor at Dark Reading. In this role he focuses on product and technology coverage for the publication. In addition he works on audio and video programming for Dark Reading and contributes to activities at Interop ITX, Black Hat, INsecurity, and ... View Full Bio
 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 6/5/2020
How AI and Automation Can Help Bridge the Cybersecurity Talent Gap
Peter Barker, Chief Product Officer at ForgeRock,  6/1/2020
Cybersecurity Spending Hits 'Temporary Pause' Amid Pandemic
Kelly Jackson Higgins, Executive Editor at Dark Reading,  6/2/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: What? IT said I needed virus protection!
Current Issue
How Cybersecurity Incident Response Programs Work (and Why Some Don't)
This Tech Digest takes a look at the vital role cybersecurity incident response (IR) plays in managing cyber-risk within organizations. Download the Tech Digest today to find out how well-planned IR programs can detect intrusions, contain breaches, and help an organization restore normal operations.
Flash Poll
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-13897
PUBLISHED: 2020-06-07
HESK before 3.1.10 allows reflected XSS.
CVE-2020-13894
PUBLISHED: 2020-06-07
handler/upload_handler.jsp in DEXT5 Editor through 3.5.1402961 allows an attacker to download arbitrary files via the savefilepath field.
CVE-2020-13895
PUBLISHED: 2020-06-07
Crypt::Perl::ECDSA in the Crypt::Perl (aka p5-Crypt-Perl) module before 0.32 for Perl fails to verify correct ECDSA signatures when r and s are small and when s = 1. This happens when using the curve secp256r1 (prime256v1). This could conceivably have a security-relevant impact if an attacker wishes...
CVE-2020-13890
PUBLISHED: 2020-06-06
The Neon theme 2.0 before 2020-06-03 for Bootstrap allows XSS via an Add Task Input operation in a dashboard.
CVE-2020-13889
PUBLISHED: 2020-06-06
showAlert() in the administration panel in Bludit 3.12.0 allows XSS.