xrdp is an open source RDP server. In versions through 0.10.5, xrdp does not implement verification for the Message Authentication Code (MAC) signature of encrypted RDP packets when using the "Classic RDP Security" layer. While the sender correctly generates signatures, the receiving logic lacks the necessary implementation to validate the 8-byte integrity signature, causing it to be silently ignored. An unauthenticated attacker with man-in-the-middle (MITM) capabilities can exploit this missing check to modify encrypted traffic in transit without detection. It does not affect connections where the TLS security layer is enforced. This issue has been fixed in version 0.10.6. If users are unable to immediately upgrade, they should configure xrdp.ini to enforce TLS security (security_layer=tls) to ensure end-to-end integrity.
| Métrique | Valeur | Interprétation |
|---|---|---|
|
AV (Vecteur d'Attaque)
Attack Vector
|
Network (N)
|
Exploit possible à distance via réseau (HTTP, API, etc.) |
|
AC (Complexité d'Attaque)
Attack Complexity
|
Low (L)
|
Peu de conditions requises pour exploiter |
|
PR (Privilèges Requis)
Privileges Required
|
None (N)
|
Aucune authentification requise |
|
UI (Interaction Utilisateur)
User Interaction
|
None (N)
|
Aucune interaction utilisateur nécessaire |
|
S (Périmètre)
Scope
|
Unchanged (U)
|
Impact reste dans le périmètre du composant compromis |
|
C (Impact Confidentialité)
Confidentiality Impact
|
None (N)
|
Aucune divulgation d'informations |
|
I (Impact Intégrité)
Integrity Impact
|
High (H)
|
Modification totale des données possible |
|
A (Impact Disponibilité)
Availability Impact
|
Low (L)
|
Interruption partielle du service possible |
xrdp: RDP MAC signature (dataSignature) never verified on receive — integrity bypass in non-TLS mode