A vulnerability was found in axTLS up to 2.1.3. It has been rated as critical. This issue affects the function sig_verify of the file x509.c of the component PKCS #1 Handler. The manipulation as part of a Certificate leads to a signature verification vulnerability (Impersonation). Using CWE to declare the problem leads to CWE-347. The product does not verify, or incorrectly verifies, the cryptographic signature for data. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In sig_verify() in x509.c in axTLS version 2.1.3 and before, the PKCS#1 v1.5 signature verification does not reject excess data after the hash value. Consequently, a remote attacker can forge signatures when small public exponents are being used, which could lead to impersonation through fake X.509 certificates. This is a variant of CVE-2006-4340.

The bug was discovered 11/05/2018. The weakness was released 11/07/2018 (Website). The advisory is shared at sourceforge.net. The identification of this vulnerability is CVE-2018-16150 since 08/29/2018. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 2 days. During that time the estimated underground price was around $0-$5k.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Productinfo

Name

• axTLS

Version

• 2.1.0
• 2.1.1
• 2.1.2
• 2.1.3

License

• open-source

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CPE 2.2info

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