SSL Certificate Signed Using Weak Hashing Algorithm (Known CA)

info Nessus Plugin ID 95631


A known CA SSL certificate in the certificate chain has been signed using a weak hashing algorithm.


The remote service uses a known CA certificate in the SSL certificate chain that has been signed using a cryptographically weak hashing algorithm (e.g., MD2, MD4, MD5, or SHA1). These signature algorithms are known to be vulnerable to collision attacks (CVE-2004-2761, for example). An attacker can exploit this to generate another certificate with the same digital signature, allowing the attacker to masquerade as the affected service.

Note that this plugin reports all SSL certificate chains signed with SHA-1 that expire after January 1, 2017 as vulnerable. This is in accordance with Google's gradual sunsetting of the SHA-1 cryptographic hash algorithm.

Note that this plugin will only fire on root certificates that are known certificate authorities as listed in Tenable Community Knowledge Article 000001752. That is what differentiates this plugin from plugin 35291, which will fire on any certificate, not just known certificate authority root certificates.

Known certificate authority root certificates are inherently trusted and so any potential issues with the signature, including it being signed using a weak hashing algorithm, are not considered security issues.


Contact the Certificate Authority to have the certificate reissued.

See Also

Plugin Details

Severity: Info

ID: 95631

File Name: ssl_weak_hash_ca.nasl

Version: 1.15

Type: remote

Family: General

Published: 12/8/2016

Updated: 10/12/2022

Supported Sensors: Nessus

Risk Information

Vulnerability Information

CPE: cpe:/a:ietf:md5, cpe:/a:ietf:x.509_certificate

Required KB Items: SSL/Chain/KnownCA/WeakHash

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 8/18/2004

Reference Information

BID: 11849, 33065

CWE: 310