Bug 479655 (CVE-2009-0125)

Summary:	CVE-2009-0125 libnasl: OpenSSL incorrect checks for malformed signatures
Product:	[Other] Security Response	Reporter:	Jan Lieskovsky <jlieskov>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	andreas.bierfert
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
URL:	http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=511517
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2009-01-22 08:33:35 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Jan Lieskovsky 2009-01-12 11:34:22 UTC

The library routines package for NASL (the scripting language designed for the Nessus security scanner) incorrectly checked the result after
calling the DSA_do_verify function, allowing a malformed signature
to be treated as a good signature rather than as an error.  This issue
affected the signature checks on DSA keys used with SSL/TLS.

Relevant part of the code (nasl/nasl_crypto2.c):
647   if (DSA_do_verify((unsigned char*)data, datalen, sig, dsa))
648      retc->x.i_val = 1;

Proposed patch:
- if (DSA_do_verify((unsigned char*)data, datalen, sig, dsa))
+ if (DSA_do_verify((unsigned char*)data, datalen, sig, dsa) == 1)

References:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=511517

This issue is related with recent OpenSSL's CVE-2008-5077 flaw.

Comment 1 Jan Lieskovsky 2009-01-12 11:35:13 UTC

This issue affects all versions of the libnasl package, as shipped
with Fedora releases of 9, 10 and devel.

Please fix.

Comment 2 Jan Lieskovsky 2009-01-16 14:11:51 UTC

Common Vulnerabilities and Exposures assigned an identifier CVE-2009-0125 to
the following vulnerability:

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.

References:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-0125
http://openwall.com/lists/oss-security/2009/01/12/4
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=511517
http://cvs.fedoraproject.org/viewvc/rpms/libnasl/F-10/libnasl.spec?r1=1.16&r2=1.17

Comment 3 Tomas Hoger 2009-01-22 08:33:35 UTC

Nessus upstream authors disputed this as a security issue:
  http://attrition.org/pipermail/vim/2009-January/002133.html

So while this is a bug, it's not considered security issue upstream.

Comment 4 Fedora Update System 2009-01-24 02:37:58 UTC

libnasl-2.2.11-3.fc10, nessus-core-2.2.11-1.fc10, nessus-libraries-2.2.11-1.fc10 has been pushed to the Fedora 10 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 5 Fedora Update System 2009-01-24 02:41:13 UTC

libnasl-2.2.11-3.fc9, nessus-core-2.2.11-1.fc9, nessus-libraries-2.2.11-1.fc9 has been pushed to the Fedora 9 stable repository.  If problems still persist, please make note of it in this bug report.