Alphabets 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 machines 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
Chronicles 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:
The 3 Cybersecurity Rules of Trust
What You Need to Know About Zero Trust Security
Data Security: Think Beyond the Endpoint
Effective Pen Tests Follow These 7 Steps

Last News
▸ ArcSight prepares for future at user conference post HP acquisition. ◂ Discovered: 07/01/2025 Category: security	▸ Samsung Epic 4G: First To Use Media Hub ◂ Discovered: 07/01/2025 Category: security	▸ Many third-party software fails security tests ◂ Discovered: 07/01/2025 Category: security

**Cyber Security Categories**
Google Dorks Database	Exploits Vulnerability	Exploit Shellcodes

CVE List

Tools/Apps

News/Aarticles

Phishing Database

Deepfake Detection

Trends/Statistics & Live Infos

Tags:
Alphabets Chronicle Explores Code-Signing Abuse in the Wild