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

5/31/2016
01:00 PM
Connect Directly
Twitter
RSS
E-Mail
50%
50%

Wekby 'Pisloader' Abuses DNS

New malware family 'pisloader' uses DNS requests for command and control.

As enterprise IT continues to ignore the security of outbound DNS traffic, the criminals are starting to take advantage of the blind spot. Researchers with Palo Alto Networks last week found yet another prime example of attacker preference for DNS last week with the emergence of a new malware variant that uses DNS requests as cover for its command-and-control (C2) communication with infected network assets.

Dubbed "pisloader" by Palo Alto's Unit 42 research team in its report last week, the new malware shows some striking similarities to the HTTPBrowser family in its command structure and naming conventions, as well as its metadata. It is another product of the Wekby crime group, which is known for its rampant use of HTTPBrowser, which leads researchers to believe that pisloader is a variant of that malware family.

The biggest highlight of the new variant is its use of DNS as a C2 protocol, but it is armed with other obfuscation techniques to make security researchers' jobs more difficult, including using return-oriented programming and garbage assembly instructions in the payload. 

"The malware is actually quite simplistic once the obfuscation and garbage code is ignored. It will begin by generating a random 10-byte alpha-numeric header. The remaining data is base32-encoded, with padding removed. This data will be used to populate a subdomain that will be used in a subsequent DNS request for a TXT record," write the researchers. "The use of DNS as a C2 allows pisloader to bypass certain security products that may not be inspecting this traffic correctly."

According to the 2016 Cisco Annual Security Report, approximately 69% of organizations today don't monitor or control recursive DNS traffic. Attackers love this visibility gap and Cisco reports that 92% of malware today uses DNS to establish C2 communication, exfiltrate data, or redirect traffic.

Specifically using DNS for C2 is not necessarily standard operating procedure for malware today, but the practice is growing in prevalence and pisloader is one among several notable samples picking up on this in the last few years, including the PlugX remote access tool (RAT) and the C3PRO-RACCOON malware that was highlighted by Forcepoint Security Labs in its in-depth study of the Jaku botnet this spring.

In the same vein, attackers are also taking advantage of DNS as a way to exfiltrate data by using DNS tunneling tools to encode data and utilize outbound Port 53 traffic to fly under the radar of many filtering tools. Earlier this month, FireEye recently brought attention to an example of a malware sample using DNS exfiltration that has been plaguing banks in the Middle East.

Security experts warn that enterprises need to take better care monitoring controlling DNS traffic, particularly outbound Port 53 traffic, in order to get a handle on threats like pisloader that will increasingly hit their networks as the crooks try to press their advantage.

"DNS is this underlying infrastructure of the entire Internet and a lot of times it's not given very much attention," says Angela Knox, senior director of engineering and threat research at network security firm Cloudmark. "But because it's so ubiquitous and often not given attention, it's a really great channel for the malicious actors to use."

Related Content:

Ericka Chickowski specializes in coverage of information technology and business innovation. She has focused on information security for the better part of a decade and regularly writes about the security industry as a contributor to Dark Reading.  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 9/17/2020
Cybersecurity Bounces Back, but Talent Still Absent
Simone Petrella, Chief Executive Officer, CyberVista,  9/16/2020
Meet the Computer Scientist Who Helped Push for Paper Ballots
Kelly Jackson Higgins, Executive Editor at Dark Reading,  9/16/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Special Report: Computing's New Normal
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
How IT Security Organizations are Attacking the Cybersecurity Problem
How IT Security Organizations are Attacking the Cybersecurity Problem
The COVID-19 pandemic turned the world -- and enterprise computing -- on end. Here's a look at how cybersecurity teams are retrenching their defense strategies, rebuilding their teams, and selecting new technologies to stop the oncoming rise of online attacks.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-14180
PUBLISHED: 2020-09-21
Affected versions of Atlassian Jira Service Desk Server and Data Center allow remote attackers authenticated as a non-administrator user to view Project Request-Types and Descriptions, via an Information Disclosure vulnerability in the editform request-type-fields resource. The affected versions are...
CVE-2020-14177
PUBLISHED: 2020-09-21
Affected versions of Atlassian Jira Server and Data Center allow remote attackers to impact the application's availability via a Regex-based Denial of Service (DoS) vulnerability in JQL version searching. The affected versions are before version 7.13.16; from version 7.14.0 before 8.5.7; from versio...
CVE-2020-14179
PUBLISHED: 2020-09-21
Affected versions of Atlassian Jira Server and Data Center allow remote, unauthenticated attackers to view custom field names and custom SLA names via an Information Disclosure vulnerability in the /secure/QueryComponent!Default.jspa endpoint. The affected versions are before version 8.5.8, and from...
CVE-2020-25789
PUBLISHED: 2020-09-19
An issue was discovered in Tiny Tiny RSS (aka tt-rss) before 2020-09-16. The cached_url feature mishandles JavaScript inside an SVG document.
CVE-2020-25790
PUBLISHED: 2020-09-19
** DISPUTED ** Typesetter CMS 5.x through 5.1 allows admins to upload and execute arbitrary PHP code via a .php file inside a ZIP archive. NOTE: the vendor disputes the significance of this report because "admins are considered trustworthy"; however, the behavior "contradicts our secu...