Vulnerabilities / Threats

4/25/2018
10:00 AM
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
100%
0%

Low-Cost Crimeware Kit Gaining Popularity in Underground Markets

At $150 for a three-month subscription, Rubella Malware Builder presents a threat to enterprises, Flashpoint says.

When it comes to malware and cybercriminals, sometimes "cheap" and "fast" clearly trumps "tested" and "sophisticated."

That's the case with Rubella Macro Builder, a recently discovered crimeware kit that, despite being new and relatively unsophisticated, has been gaining popularity among cybercriminals - including members of the suspected Russian gang behind the Panda banking malware.

Security vendor Flashpoint, which issued an advisory on the threat this week, described Rubella as enabling criminals to generate Microsoft Word (.doc) and Microsoft Excel (.xls) payloads.  "The Rubella-generated malware acts as a first-stage loader for other subsequent malware downloads and installations on targeted machines," says Vitali Kremez, director of research for Flashpoint.

Since it surfaced in February, Rubella Macro Builder has been used as a first-stage loader in one of the most recent Panda campaigns. The group behind the distribution appears to have targeted victims through various social media platforms and through webinjects, Flashpoint says.

"Flashpoint identified Rubella malware infection leading to the execution of the Panda banking malware version 2.6.6 and Gootkit banking malware," Kremez says. Panda and Gootkit are designed to harvest credentials, infect browsers through webinjects and enable remote PC access via a hidden virtual network-computing module, he says.

When it first surfaced in February, the authors of the Rubella crimeware kit priced it at a relatively low $500 per month. Since then, prices for the kit have dropped even further to just around $150 for a three-month subscription even as it has acquired several new capabilities, according to FlashPoint.

The Rubella crimeware kit currently includes support for XOR and Base64 encryption algorithms, PowerShell, Microsoft.XMLHTTP, and Bitsadmin download methods and multiple payload execution options including Visual Basic Script and JavaScript.

Rubella Macro Builder does not exploit any security vulnerabilities. Rather, it relies on social engineering techniques to force victims to enable malicious macro execution to run it, Kremez says. It is typically distributed to intended victims via Microsoft Word or Excel email attachments during spam campaigns. It comes with some rudimentary but nevertheless effective obfuscation methods for bypassing basic AV tools.

"The macro builder has a clear appeal for cybercriminals: it’s cheap, fast, and can defeat basic static anti-virus detection," Kremez says.

Rubella is somewhat similar to ThreadKit, a more advanced malware kit that researchers at Proofpoint discovered last October and described in an alert in March. ThreadKit, like Rubella is a Microsoft Office document exploit builder, but packs more features, including a mechanism for reporting infection statistics back to the operators of the malware.

ThreadKit has been used quite extensively to spread numerous malware payloads including Trickbot and remote access Trojans like Loki Bot and FormBook. One well-known crime group that has been using the kit is the Cobalt Gang, a threat actor associated with various ATM heists.

"Microsoft Office macro-based malware appears to still be threat actors' preferred method for obtaining initial access to compromised machines," Flashpoint said in its advisory. Microsoft Office-based loader malware like Rubella work well as an intial decoy because they look like commonly exchanged Word and Excel documents and attachments.

According to the security vendor, Rubella Macro Builder represents a moderate threat for enterpises given its ability to beat static AV tools and its low pricing model. To mitigate their exposure to the threat, organizations should pay attention to email messages with suspicious Word or Excel attachments, especially those that ask permission to 'Enable Content' for running macros, FlashPoint said.

Related Content:

Interop ITX 2018

Join Dark Reading LIVE for an intensive Security Pro Summit at Interop ITX and learn from the industry’s most knowledgeable IT security experts. Check out the agenda here.

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
johnwicked
50%
50%
johnwicked,
User Rank: Apprentice
4/26/2018 | 1:53:12 PM
Rubella
Why do you have to say it is not properly tested? I put a lot of time coding this tool, so atleast have the decency to elaborate on such claims. :-(

It might not be sophisticated. But it does bypass protection on both scantime and runtime and works properly. I do not see the issue with it being not sophistcated as long as it works properly. Better to have something usual and working instead of something flashy and non-functional in the pentesting industry, right?

I wish you a nice day, keep following your passion in the security industry.
White House Cybersecurity Strategy at a Crossroads
Kelly Jackson Higgins, Executive Editor at Dark Reading,  7/17/2018
Lessons from My Strange Journey into InfoSec
Lysa Myers, Security Researcher, ESET,  7/12/2018
What's Cooking With Caleb Sima
Kelly Jackson Higgins, Executive Editor at Dark Reading,  7/12/2018
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Current Issue
Flash Poll
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2016-9574
PUBLISHED: 2018-07-19
nss before version 3.30 is vulnerable to a remote denial of service during the session handshake when using SessionTicket extension and ECDHE-ECDSA.
CVE-2017-2673
PUBLISHED: 2018-07-19
An authorization-check flaw was discovered in federation configurations of the OpenStack Identity service (keystone). An authenticated federated user could request permissions to a project and unintentionally be granted all related roles including administrative roles.
CVE-2017-7481
PUBLISHED: 2018-07-19
Ansible before versions 2.3.1.0 and 2.4.0.0 fails to properly mark lookup-plugin results as unsafe. If an attacker could control the results of lookup() calls, they could inject Unicode strings to be parsed by the jinja2 templating system, resulting in code execution. By default, the jinja2 templati...
CVE-2018-12911
PUBLISHED: 2018-07-19
WebKitGTK+ 2.20.3 has an off-by-one error, with a resultant out-of-bounds write, in the get_simple_globs functions in ThirdParty/xdgmime/src/xdgmimecache.c and ThirdParty/xdgmime/src/xdgmimeglob.c.
CVE-2018-14404
PUBLISHED: 2018-07-19
A NULL pointer dereference vulnerability exists in the xpath.c:xmlXPathCompOpEval() function of libxml2 through 2.9.8 when parsing an invalid XPath expression in the XPATH_OP_AND or XPATH_OP_OR case. Applications processing untrusted XSL format inputs with the use of the libxml2 library may be vulne...