Financially motivated actor breaks certificate parsing to avoid detection

Code signatures on Windows executables provide guarantees about the integrity of a signed executable, as well as information about the identity of the signer.
Attackers who are able to obscure their identity in signatures without affecting the integrity of the signature can avoid detection longer and extend the lifetime of their code-signing certificates to infect more systems.

OpenSUpdater, a known family of unwanted software which violates our policies and is harmful to the user experience, is used to download and install other suspicious programs.
The actor behind OpenSUpdater tries to infect as many users as possible and while they do not have specific targeting, most targets appear to be within the United States and prone to downloading game cracks and grey-area software.

Groups of OpenSUpdater samples are often signed with the same code-signing certificate, obtained from a legitimate certificate authority.
Since mid-August, OpenSUpdater samples have carried an invalid signature, and further investigation showed this was a deliberate attempt to evade detection.
In these new samples, the signature was edited such that an End of Content (EOC) marker replaced a NULL tag for the ‘parameters’ element of the SignatureAlgorithm signing the leaf X.509 certificate.

EOC markers terminate indefinite-length encodings, but in this case an EOC is used within a definite-length encoding (l= 13).

Sign Up For Threat Alerts

Loading...
Threats Icon

Aug 11, 2022

Cisco Talos shares insights related to recent...

Initial access to the Cisco VPN was achieved via the successful compromise of a Cisco...

Threats Icon

Aug 11, 2022

Andariel deploys DTrack and Maui ransomware

The CISA published an alert, entitled, "North Korean State-Sponsored Cyber Actors Use Maui Ransomware To...

Threats Icon

Aug 09, 2022

Albanian Government Organizations Targeted By Possible Iranian...

Mandiant identified the ROADSWEEP ransomware family and a Telegram persona which targeted the Albanian government...

Threats Icon

Aug 08, 2022

BumbleBee Roasts Its Way to Domain Admin

Threat actors used BumbleBee as the initial access vector. BumbleBee is a malware loader that...

Threats Icon

Aug 08, 2022

RapperBot – new evolving malware

FortiGuard Labs has been tracking a rapidly evolving IoT malware family known as "RapperBot". This...

Threats Icon

Aug 04, 2022

Google Drive And Dropbox Used By APT29...

Cloaked Ursa (aka: APT29) has been targeting governmental entities in several countries with spear-phishing campaigns...

Threats Icon

Aug 03, 2022

Manjusaka: A Chinese sibling of Sliver and...

Cisco Talos recently discovered a new attack framework called "Manjusaka" being used in the wild...

Threats Icon

Aug 03, 2022

macOS Targeted With The CloudMensis Multi-Staged Malware

ESET researchers discovered a previously unknown macOS backdoor that spies on users of the compromised...

Threats Icon

Aug 01, 2022

Attackers Target Ukraine With GoMet Backdoor

Since the Russian invasion of Ukraine began, Ukrainians have been under a nearly constant barrage...

Threats Icon

Jul 31, 2022

Untangling KNOTWEED: European private-sector offensive actor using...

The Microsoft Threat Intelligence Center (MSTIC) and the Microsoft Security Response Center (MSRC) found a...

Threats Icon

Jul 31, 2022

Untangling KNOTWEED: European private-sector offensive actor using...

The Microsoft Threat Intelligence Center (MSTIC) and the Microsoft Security Response Center (MSRC) found a...

Threats Icon

Jul 26, 2022

EvilNum Targets Cryptocurrency, Forex, Commodities

Proofpoint Threat Research observed the group Proofpoint calls TA4563 targeting various European financial and investment...

Threats Icon

Jul 25, 2022

Lightning Framework: New Undetected “Swiss Army Knife”...

Lightning is a previously undocumented and undetected Linux threat. Lightning is a modular framework we...

Threats Icon

Jul 24, 2022

Redeemer Ransomware

Redeemer 2.0 Being Distributed Via Affiliate Program Cyble Research Labs has constantly been tracking emerging...

Threats Icon

Jul 21, 2022

Cobalt Strikes again: UAC-0056 continues to target...

The Malwarebytes Threat Intelligence team recently reviewed a series of cyber attacks against Ukraine that...