VULNARCHIVE

Security advisory: Pre-authentication RCE in Plastic SCM (Unity Version Control On-Prem) 11.0.16.10303 (Unity Technologies)

disclosure via Fulldisclosure ·

0day Rubbish Research Team is publicly disclosing a vulnerability in Plastic SCM (Unity Version Control On-Prem) 
11.0.16.10303 (Unity Technologies). The research is published and a proof-of-concept is available.

Pre-authentication RCE (CVSS 9.8, pre-authentication)

Plastic SCM ships a self-developed binary version-control protocol on port 8087, reachable by default on 0.0.0.0. Under 
the default NameWorkingMode, the server validates only that a client-declared username maps to a local OS account and 
never checks a password; LocalGroupSEIDProvider.CheckPassword is an empty no-op. Combined with a default EVERYBODY ACL 
that grants ALL_PERMISSIONS (including mktrigger) to any name-only-authenticated user, an unauthenticated attacker can 
declare an administrative username (leaked unauthenticated via GetRepositoryServerInfo), create a server-side trigger 
whose Path is fully attacker-controlled, and trigger it with a repository operation. TriggerProcess.ExecuteTrigger 
feeds the Path straight into Process.Start as the FileName with no sandbox, path allowlist, or signature check, 
yielding RCE as the plasticd service account (Linux: plasticscm uid=217; Windows: local Administrator). The only 
non-network prerequisite is one local OS username, which the protocol itself leaks.

Impact: Full compromise of the version-control server and all repositories, and arbitrary command execution as the 
plasticd service account; the attacker can read source code and repository metadata, create triggers, alter 
repositories, and persist access.

Advisory: https://0day-rubbish.com/blog/plastic-scm-unauth-8087-rce

PoC and full analysis: https://github.com/Exploit-Garbage/0day-Rubbish

-- 
0day Rubbish Research Team
https://0day-rubbish.com
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