A code signing certificate allows an application developer to sign their software before publishing to the web and the end-users can verify the author’s identity and ensure the software has not been altered.
Security researchers from ESET spotted a new malware campaign that uses stolen code Signing certificate from D-Link Corporation to make it appear like a like legitimate application.
It appears the hackers have stolen the code-signing certificate as the non-malicious D-Link software also signed with same code signing certificate. ESET notified D-Link about the signed malicious binary and the Code Signing certificate revoked on July 3, 2018.
Malware Signed With stolen Code Signing Certificate
According to ESET two malware using the stolen certificate, the Plead malware, a remotely controlled backdoor, and a related password stealer component.
Along with D-Link certificate, a Taiwanese security company(Changing Information Technology Inc) certificate also used in signing the malicious binaries. Changing Information Technology Inc certificate was revoked on July 4, 2017.
The signed binaries are highly obfuscated, it downloads binary blob from the remote server, which downloads the final Plead backdoor. The password stealer component stealer component is capable of collecting saved passwords from applications like Google Chrome, Microsoft Internet Explorer, Microsoft Outlook and Mozilla Firefox.
According to recent investigation reports, there is a number of Underground market vendor’s selling the standard as well as the highly trusted EV codesigning certificates.