Description
Vulnerability in the access control system of the GAMS licensing system that allows unlimited valid licenses to be generated, bypassing any usage restrictions. The validator uses an insecure checksum algorithm; knowing this algorithm and the format of the license lines, an attacker can recalculate the checksum and generate a valid license to grant themselves full privileges without credentials or access to the source code, allowing them unrestricted access to GAMS's mathematical models and commercial solvers.
Problem types
CWE-639 Authorization Bypass Through User-Controlled Key
Product status
Any version
Credits
Juan Embid Sánchez
Francisco Guerrero Gallardo
References
www.incibe.es/...orization-bypass-gams-gams-development-corp
www.gams.com/latest/docs/RN_51.html
