VULNARCHIVE

Security advisory: multiple vulnerabilities including JWT forgery / authentication bypass, Pre-authentication SYSTEM RCE in CIRCUTOR PowerStudio SCADA WAVE 24.11.6.0 (CIRCUTOR S.A.)

disclosure via Fulldisclosure ·

0day Rubbish Research Team is publicly disclosing 2 vulnerabilities in CIRCUTOR PowerStudio SCADA WAVE 24.11.6.0 
(CIRCUTOR S.A.). The research is published and a proof-of-concept is available.

Vulnerability 1: Pre-authentication SYSTEM RCE (CVSS 9.8, pre-authentication)

The native engine PwrStudio.exe runs as the Windows service CircutorPowerStudioScadaServer under NT AUTHORITY\SYSTEM. 
The shared fail-open JWT library (see companion advisory) accepts a forged alg=none JWT with role=Admin. Combined with 
a path-traversal write of a malicious default.xeve events configuration (containing a shellExecute action) against 
PSSWidgets (port 8105) and an HTTP engine restart against PSSAdministrator (port 8089), an unauthenticated attacker 
forces the engine to reload the configuration and fire XCEventActionShellExecute::Execute, which reaches CreateProcessW 
with attacker-controlled arguments as SYSTEM. Under a strict default deployment where 8089 is loopback-only with no 
forwarding path, the chain does not close for a pure-remote unauthenticated attacker; once 8089 is reachable (reverse 
proxy, rebind, same-host, or same segment), it is a full unauthenticated remote SYSTEM RCE.

Impact: Arbitrary command execution as NT AUTHORITY\SYSTEM on the SCADA host; the attacker controls the SCADA engine, 
the event configuration, and the underlying Windows host.

Advisory: https://0day-rubbish.com/blog/circutor-powerstudio-unauth-shellExecute-rce

Vulnerability 2: JWT forgery / authentication bypass (CVSS 8.6, pre-authentication)

Every .NET Core microservice registers JWT Bearer authentication via a shared extension method configured fail-open: a 
custom SignatureValidator that always returns a non-null token without validating the signature, 
RequireSignedTokens=false, ValidateIssuerSigningKey=false, ValidateIssuer=false, ValidateAudience=false, and an 
OnAuthenticationFailed handler that silently swallows exceptions. Any attacker-crafted alg=none JWT with any role claim 
is accepted as a valid authenticated identity by every microservice's AdminSecure/UserSecure policy. No credentials, no 
signing key, and no user account are required; only network reachability to the target microservice port. This is an 
authentication-bypass/identity-forgery primitive that compromises the product's entire authentication trust root and is 
the auth-bypass primitive that enables the companion shellExecute RCE chain.

Impact: Impersonate any Admin/User role and call any protected endpoint: stop/start the SCADA engine or microservices 
(DoS), push configuration, upload/download/delete files, configure external communication, and manage licenses; no 
credentials required.

Advisory: https://0day-rubbish.com/blog/circutor-powerstudio-jwt-alg-none-identity-forgery

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

-- 
0day Rubbish Research Team
https://0day-rubbish.com
_______________________________________________
Sent through the Full Disclosure mailing list
https://nmap.org/mailman/listinfo/fulldisclosure
Web Archives & RSS: https://seclists.org/fulldisclosure/