Bug 255576 (CVE-2009-0125)

Summary:	net-analyzer/libnasl<=2.2.11 DSA_do_verify certificate chain bypass (CVE-2009-0125)
Product:	Gentoo Security	Reporter:	Stefan Behte (RETIRED) <craig>
Component:	Vulnerabilities	Assignee:	Gentoo Security <security>
Status:	RESOLVED INVALID
Severity:	minor	CC:	netmon
Priority:	High
Version:	unspecified
Hardware:	All
OS:	Linux
URL:	https://bugzilla.redhat.com/show_bug.cgi?id=479655
Whiteboard:	B4 [ebuild]
Package list:		Runtime testing required:	---

Description Stefan Behte (RETIRED) gentoo-dev

2009-01-19 23:53:52 UTC

CVE-2009-0125 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2009-0125):
  nasl/nasl_crypto2.c in the Nessus Attack Scripting Language library
  (aka libnasl) 2.2.11 does not properly check the return value from
  the OpenSSL DSA_do_verify function, which allows remote attackers to
  bypass validation of the certificate chain via a malformed SSL/TLS
  signature, a similar vulnerability to CVE-2008-5077.

Comment 1 Robert Buchholz (RETIRED) gentoo-dev

2009-01-21 11:48:14 UTC

Upstream states:
> From: Renaud Deraison <deraison nessus org>
> Date: January 18, 2009 10:43:29 PM CEST
> 
> I wanted to dispute the existence of CVE-2009-0125 (libnasl misusing the 
> return value of DSA_do_verify()) : while we do misuse this function (this is 
> a bug), it has absolutely no security ramification.
> 
> To give you some context, the function DSA_do_verify() is called by the nasl 
> function  dsa_do_verify() which is used when Nessus attempts to log into a 
> remote SSH server.
> 
> If an attacker were to control a rogue SSH server, then he would be better 
> off submitting a perfectly valid signature instead of a malformed one, and we 
> would log into it anyways. Hence, there is absolutely no security risk 
> associated with the misuse of this function.