In verify_emsa_pkcs1_signature() in gmp_rsa_public_key.c in the gmp plugin in strongSwan 4.x and 5.x before 5.7.0, the RSA implementation based on GMP does not reject excess data after the encoded algorithm OID during PKCS#1 v1.5 signature verification. Similar to the flaw in the same version of strongSwan regarding digestAlgorithm.parameters, a remote attacker can forge signatures when small public exponents are being used, which could lead to impersonation when only an RSA signature is used for IKEv2 authentication.
| Date Added | Due Date | Vulnerability Name | Required Action |
|---|---|---|---|
| N/A |
| Type | Version | Base score | Base severity | Vector |
|---|---|---|---|---|
| Secondary | 3.1 | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| Primary | 3.0 | 7.5 | HIGH | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| Primary | 2.0 | 5.0 | MEDIUM | AV:N/AC:L/Au:N/C:N/I:P/A:N |