Endpoint

7/13/2018
02:20 PM
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
50%
50%

GandCrab Ransomware Continues to Evolve But Can't Spread Via SMB Shares Yet

Recent fears that this year's most prolific ransomware threat has acquired new WannaCry-like propagation capabilities appear unfounded at the moment.

The authors of GandCrab, a ransomware sample that in less than six months has become the biggest threat in its category, are continuing to update and tweak the malware to make it harder to stop. But fears in recent days that they might have added a new WannaCry-like capability for spreading GandCrab via SMB shares appear unfounded at the moment.

Security vendor Fortinet recently discovered a new version (4.1) of GandCrab in the wild. Like its predecessor, released just two days prior to the new discovery, the latest version is being distributed through compromised websites designed to appear like download sites for cracked applications. And as with version 4, version 4.1, like the Petya ransomware tool, also uses the faster Salsa2.0 stream cipher to encrypt data instead of the RSA-2048 encryption used in early GandCrab releases.

The biggest difference in GandCrab 4.1 is that it contains a long, hard-coded list of websites to which the malware connects. Once connected to a URL in the list, the malware sends it data — such as the IP address, username, computer name, network domain, and, if present, a list of anti-malware tools on the system — from the infected system.

Interestingly, according to Fortinet, there is no evidence that any one of the websites in GandCrab 4.1's hard-coded list has actually been compromised. And there's little logical reason why the authors of GandCrab would want to send victim information to so many hosts at once anyway, when all they really need is to have the information sent to one system. The only explanations, according to the security firm, are that the creators of GandCrab are testing the functionality or have put it there as a diversionary tactic.

"Unfortunately, we really don't know what the motivation behind the author truly is and how it makes sense, given that one functional URL can retrieve this information as well," says Val Saengphaibul, senior threat researcher at Fortinet's FortiGuard Labs. "It perhaps might be a smoke screen to throw off analysis or perhaps something experimental that might make sense afterward."

Fortinet's analysis also showed that GandCrab 4.1 is designed to kill numerous processes, such as msftesql.exe, sqlagent.exe, oracle.exe, msaccess.exe, powerpnt.exe, and wordpad.exe, so it can ensure full encryption of any targeted files.

Killing the processes ensures that high-value files of the victim — Microsoft Office Files, Steam, etc. — are encrypted, Saengphaibul says. "Any open, in-progress file is also shut down to allow it to be overwritten to ensure that the full encryption routine takes place on those as well," he says.

One thing that Fortinet's researchers did not find, however, is any evidence that GandCrab is now able to spread via SMB shares, such as WannaCry and Petya/NotPetya. That would have made the threat posed by the malware substantially greater.

According to the vendor, its researchers have not able to find any function in GandCrab 4.1 that would support this capability. Therefore, any fears about exploit propagation via SMB have to be considered as speculative for the moment, the vendor said.

Since first surfacing in January, GandCrab has caught the attention of the security community both for how prolific it has been and for how its authors have managed to keep one step ahead of defenders. As of March, when numbers were last available, the malware had infected over 50,000 systems and netted its operators over $600,000 in ransom payments.

Security researchers have previously noted how the creators of the tool appear to have adopted an agile-like development approach to the malware, including the way it is maintained. From an initially buggy release, the malware has kept evolving, with each version featuring tweaks designed to address shortcomings in previous iterations. Among the several updates is one that surfaced in version 4.0 that gives GandCrab the ability to encrypt data without first connecting to its C2 server, meaning it can encrypt even when an infected system is not connected to the Internet.

Even though many of the updates to the malware have been incremental in nature, they are still enough to warrant continual analysis from the security community, Saengphaibul says. "The GandCrab operation is run in true business-like fashion and focuses on a high return of infection on victims while at the same time focusing on evading antivirus technologies," he notes.

Related Content:

 

 

 

Black Hat USA returns to Las Vegas 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.

Jai Vijayan is a seasoned technology reporter with over 20 years of experience in IT trade journalism. He was most recently a Senior Editor at Computerworld, where he covered information security and data privacy issues for the publication. Over the course of his 20-year ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
iaa1000
50%
50%
iaa1000,
User Rank: Apprentice
7/22/2018 | 2:53:10 AM
Very first analysis and publication
Hello. The very first analysis and publication about GandCrab-4 Ransomware was made on July 1, 2018.

Link: id-ransomware.blogspot.com
Tips for the Aftermath of a Cyberattack
Kelly Sheridan, Staff Editor, Dark Reading,  4/17/2019
Former Student Admits to USB Killer Attack
Dark Reading Staff 4/18/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
5 Emerging Cyber Threats to Watch for in 2019
Online attackers are constantly developing new, innovative ways to break into the enterprise. This Dark Reading Tech Digest gives an in-depth look at five emerging attack trends and exploits your security team should look out for, along with helpful recommendations on how you can prevent your organization from falling victim.
Flash Poll
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2019-11320
PUBLISHED: 2019-04-18
In Motorola CX2 1.01 and M2 1.01, users can access the router's /priv_mgt.html web page to launch telnetd, as demonstrated by the 192.168.51.1 address.
CVE-2019-11321
PUBLISHED: 2019-04-18
An issue was discovered in Motorola CX2 1.01 and M2 1.01. The router opens TCP port 8010. Users can send hnap requests to this port without authentication to obtain information such as the MAC addresses of connected client devices.
CVE-2019-11322
PUBLISHED: 2019-04-18
An issue was discovered in Motorola CX2 1.01 and M2 1.01. There is a command injection in the function startRmtAssist in hnap, which leads to remote code execution via shell metacharacters in a JSON value.
CVE-2019-8999
PUBLISHED: 2019-04-18
An XML External Entity vulnerability in the UEM Core of BlackBerry UEM version(s) earlier than 12.10.1a could allow an attacker to potentially gain read access to files on any system reachable by the UEM service account.
CVE-2018-17168
PUBLISHED: 2019-04-18
PrinterOn Enterprise 4.1.4 contains multiple Cross Site Request Forgery (CSRF) vulnerabilities in the Administration page. For example, an administrator, by following a link, can be tricked into making unwanted changes to a printer (Disable, Approve, etc).