FreeRDP before 3.29.0 contains a buffer over-disclosure vulnerability in the gateway WebSocket transport (libfreerdp/core/gateway/websocket.c). The clients Pong reply reuses a fixed 1024-byte response stream whose length is not sealed to the actual received Ping payload, so a malicious gateway/WebSocket peer sending a non-empty Ping control frame causes the client to reply with an overlong Pong that discloses bytes beyond the received payload (the peer receives the masking key and can unmask the reply). A zero-length Ping reaches an assertion and terminates the client (denial of service).
Weakness
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
Potential Mitigations
Related Attack Patterns
References
- https://github.com/FreeRDP/FreeRDP/commit/f3b4347105114fe7453828736bea069999af319f
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-8v6m-2cmc-chx9
- https://www.vulncheck.com/advisories/freerdp-before-websocket-ping-buffer-over-disclosure
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-8v6m-2cmc-chx9