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.

Threat Intelligence

9/13/2019
04:15 PM
Connect Directly
Twitter
LinkedIn
Google+
RSS
E-Mail
50%
50%

Malware Linked to Ryuk Targets Financial & Military Data

A newly discovered campaign, packing traces of Ryuk ransomware, aims to steal confidential information.

New malware bearing similarities to Ryuk ransomware has been discovered in a campaign attempting to steal files containing confidential military, financial, and law enforcement data.

This campaign, which was detected by the MalwareHunterTeam, does not encrypt the target's data and demand a ransom as Ryuk normally does. Instead, it searches victims' computers for sensitive files, steals them, and uploads the information to a site under the operators' control.

It has not yet been determined how the Ryuk lookalike lands on target machines. When it does, it scans for specific Word and Excel files, checking for strings kept on a blacklist, BleepingComputer explains in a report. When a file or folder matches a string, the malware stops checking it. If a document passes the blacklist, it verifies whether the file is valid.

If so, the malware compares its name to a list of 77 strings seemingly picked to lead the operator to sensitive information: "military," "classified," "finance," "SWIFT," "report," "secret," "clandestine," "checking," "saving," and "routing" are all examples of terms on the list. When a file matches a term in this string, it's uploaded to a server controlled by the attackers.

Jeff Warren, general manager of products for STEALTHbits Technologies, emphasizes the simplicity of the techniques used to identify sensitive files. "With nothing more than comparing file names to a list of 77 strings, the malware is able to identify and exfiltrate sensitive information," he says. The stealer uses basic scanning to identify and mount additional shared folders, so anywhere a user has access is vulnerable to these types of attacks, Warren adds.

Ryuk Relations
This particular infection shares a few curious qualities with Ryuk ransomware. For one, it contains specific string references to ".RYK" and "RyukReadMe.txt," says cybersecurity researcher Vitali Kremez in a conversation with Dark Reading. Ryuk typically leaves victim notes as "RyukReadMe.txt," and encrypted files have the ".RYK" extension. The stealer malware seems to intentionally skip files like these, which are linked to the Ryuk ransomware.

Also like Ryuk, this malware contains specific references to the Ahnlab antivirus company and it checks for a file called Ahnlab on target machines. It also has a link to "UNIQUE_ID_DO_NOT_REMOVE," which is a string present in Ryuk ransomware, Kremez adds. The malware's file searcher and extension with blacklist logic are similar to the Ryuk routines.

"Overall, it looks like someone with the Ryuk code added additional code to make it a stealer and compiled in a different environment," he says. The code indicates this wasn't an advanced attacker. "It feels like if someone less experienced took the Ryuk code and/or tried to mimic Ryuk routines, then they copy/pasted some own code logic/code and created a new malware."

The code quality related to upper/lowercase extension check, external library dependency, and recursive routine is not good, Kremez notes. Still, the act of taking Ryuk and transforming it into a stealer is new, he points out. Ryuk's ransomware operations are linked to the TrickBot malware group, and they have robust code development. While there is no way to know who is behind this, the actor may be linked to the core Ryuk group if code was taken from them.

"We know that Ryuk is a very targeted ransomware," Kremez explains. "If this malware is part of the same group, we suspect it to be also very targeted."

Ryuk ransomware has been seen targeting businesses around the world. In April, it struck the city of Stuart, Florida, and forced servers and computers offline; last year, it hit C.E. Niehoff & Co., a small manufacturing firm. Earlier this summer, the UK's National Cyber Security Centre (NCSC) issued a warning for a new global Ryuk ransomware campaign packing Emotet and TrickBot.

Related Content:

Check out The Edge, Dark Reading's new section for features, threat data, and in-depth perspectives. Today's top story: "Escaping Email: Unlocking Message Security for SMS, WhatsApp."

Kelly Sheridan is the Staff Editor at Dark Reading, where she focuses on cybersecurity news and analysis. She is a business technology journalist who previously reported for InformationWeek, where she covered Microsoft, and Insurance & Technology, where she covered financial ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Exploits Released for As-Yet Unpatched Critical Citrix Flaw
Jai Vijayan, Contributing Writer,  1/13/2020
Microsoft to Officially End Support for Windows 7, Server 2008
Kelly Sheridan, Staff Editor, Dark Reading,  1/13/2020
Active Directory Needs an Update: Here's Why
Raz Rafaeli, CEO and Co-Founder at Secret Double Octopus,  1/16/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: This comment is waiting for review by our moderators.
Current Issue
The Year in Security: 2019
This Tech Digest provides a wrap up and overview of the year's top cybersecurity news stories. It was a year of new twists on old threats, with fears of another WannaCry-type worm and of a possible botnet army of Wi-Fi routers. But 2019 also underscored the risk of firmware and trusted security tools harboring dangerous holes that cybercriminals and nation-state hackers could readily abuse. Read more.
Flash Poll
[Just Released] How Enterprises are Attacking the Cybersecurity Problem
[Just Released] How Enterprises are Attacking the Cybersecurity Problem
Organizations have invested in a sweeping array of security technologies to address challenges associated with the growing number of cybersecurity attacks. However, the complexity involved in managing these technologies is emerging as a major problem. Read this report to find out what your peers biggest security challenges are and the technologies they are using to address them.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2014-5007
PUBLISHED: 2020-01-17
Directory traversal vulnerability in the agentLogUploader servlet in ZOHO ManageEngine Desktop Central (DC) and Desktop Central Managed Service Providers (MSP) edition before 9 build 90055 allows remote attackers to write to and execute arbitrary files as SYSTEM via a .. (dot dot) in the filename pa...
CVE-2020-5397
PUBLISHED: 2020-01-17
Spring Framework, versions 5.2.x prior to 5.2.3 are vulnerable to CSRF attacks through CORS preflight requests that target Spring MVC (spring-webmvc module) or Spring WebFlux (spring-webflux module) endpoints. Only non-authenticated endpoints are vulnerable because preflight requests should not incl...
CVE-2019-17635
PUBLISHED: 2020-01-17
Eclipse Memory Analyzer version 1.9.1 and earlier is subject to a deserialization vulnerability if an index file of a parsed heap dump is replaced by a malicious version and the heap dump is reopened in Memory Analyzer. The user must chose to reopen an already parsed heap dump with an untrusted inde...
CVE-2019-19339
PUBLISHED: 2020-01-17
It was found that the Red Hat Enterprise Linux 8 kpatch update did not include the complete fix for CVE-2018-12207. A flaw was found in the way Intel CPUs handle inconsistency between, virtual to physical memory address translations in CPU's local cache and system software's Paging structure entries...
CVE-2007-6070
PUBLISHED: 2020-01-17
** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: CVE-2008-1382. Reason: This candidate is a reservation duplicate of CVE-2008-1382. Notes: All CVE users should reference CVE-2008-1382 instead of this candidate. All references and descriptions in this candidate have been removed to prevent ...