An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior).
This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products 2
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Arm Mbed_Tls
cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*
|
— |
3.6.6
|
|
Arm Tf-Psa-Crypto
cpe:2.3:a:arm:tf-psa-crypto:1.0.0:-:*:*:*:*:*:*
|
— | — |