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.

Vulnerabilities / Threats

5/22/2019
07:15 PM
Connect Directly
Twitter
LinkedIn
Google+
RSS
E-Mail
50%
50%

Alphabet's Chronicle Explores Code-Signing Abuse in the Wild

A new analysis highlights the prevalence of malware signed by certificate authorities and the problems with trust-based security.

Researchers with Chronicle, the cybersecurity company and Alphabet subsidiary, today published an analysis of its investigation into the trend of signed malware being exploited in the wild.

The process of cryptographically signing code was created to give the Windows operating system a means to distinguish good code from bad. Certificates are signed/issued by trusted certificate authorities (CAs), backed by a trusted parent CA. The purpose behind signing a Windows executable file was to mark the authenticity of code published on the Internet.

The problem is, this system is based on trust, and cybercriminals are taking advantage of it.

Malware authors buy these certificates, directly or through resellers. While a CA can revoke a certificate deemed untrustworthy — and more of them are — this remains the only way to cut down on abuse. The process creates a window during which malware has a trusted certificate.

To highlight the prevalence of this trend and problems with trust-based security, Chronicle researchers used VirusTotal, an online virus/malware scanner that analyzes suspicious files that a machine's antivirus tools may have missed. They limited this project to Windows PE Executable files, filtered out samples with fewer than 15 aggregate detections, and "aggressively" filtered out grayware files to determine the number of malware samples each CA was responsible for signing. When all was said and filtered, the researchers ended up with a total of 3,815 malware samples.

CAs that signed certificates of 100+ malware samples accounted for nearly 78% of signed malware uploaded to VirusTotal, Chronicle reports. Interestingly, there is a significant drop between CAs when considering malware samples signed. For example, COMODO RSA Code Signing CA, which has the most samples at 1,775, has almost 3.5 times the amount of Thawte SHA256 Code Signing CA, which has the next-highest number, at 509 signed malware samples. The numbers continue to fall from there: Thawte SHA256 has double the next-highest CA.

Researchers report CAs are combating the trend. More than 20% of malware samples had their certificates revoked at the time Chronicle's blog post published, a sign CAs are cracking down.

As Chronicle points out, attackers taking advantage of user trust is nothing new; however, it was believed to mostly be popular among nation-state attackers. Now, it appears the trend has grown to become a common practice among most cybercriminals armed with malware.

"The impact is amplified by the scope and scale of typical crimeware campaigns," the company reports. "Expect to see signed malware reported more frequently."

Related Content:

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
For Cybersecurity to Be Proactive, Terrains Must Be Mapped
Craig Harber, Chief Technology Officer at Fidelis Cybersecurity,  10/8/2019
A Realistic Threat Model for the Masses
Lysa Myers, Security Researcher, ESET,  10/9/2019
USB Drive Security Still Lags
Dark Reading Staff 10/9/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Current Issue
7 Threats & Disruptive Forces Changing the Face of Cybersecurity
This Dark Reading Tech Digest gives an in-depth look at the biggest emerging threats and disruptive forces that are changing the face of cybersecurity today.
Flash Poll
2019 Online Malware and Threats
2019 Online Malware and Threats
As cyberattacks become more frequent and more sophisticated, enterprise security teams are under unprecedented pressure to respond. Is your organization ready?
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2019-17593
PUBLISHED: 2019-10-14
JIZHICMS 1.5.1 allows admin.php/Admin/adminadd.html CSRF to add an administrator.
CVE-2019-17594
PUBLISHED: 2019-10-14
There is a heap-based buffer over-read in the _nc_find_entry function in tinfo/comp_hash.c in the terminfo library in ncurses before 6.1-20191012.
CVE-2019-17595
PUBLISHED: 2019-10-14
There is a heap-based buffer over-read in the fmt_entry function in tinfo/comp_hash.c in the terminfo library in ncurses before 6.1-20191012.
CVE-2019-14823
PUBLISHED: 2019-10-14
A flaw was found in the "Leaf and Chain" OCSP policy implementation in JSS' CryptoManager versions after 4.4.6, 4.5.3, 4.6.0, where it implicitly trusted the root certificate of a certificate chain. Applications using this policy may not properly verify the chain and could be vulnerable to...
CVE-2019-17592
PUBLISHED: 2019-10-14
The csv-parse module before 4.4.6 for Node.js is vulnerable to Regular Expression Denial of Service. The __isInt() function contains a malformed regular expression that processes large crafted input very slowly. This is triggered when using the cast option.