Mozilla Network Security Service (NSS): RSA signature forgery

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200610-06 / nss
Release Date	October 17, 2006
Latest Revision	October 17, 2006: 01
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
dev-libs/nss	< 3.11.3	>= 3.11.3	All supported architectures

Related bugreports: #148283

Synopsis

NSS fails to properly validate PKCS #1 v1.5 signatures.

2. Impact Information

Background

The Mozilla Network Security Service is a library implementing security features like SSL v.2/v.3, TLS, PKCS #5, PKCS #7, PKCS #11, PKCS #12, S/MIME and X.509 certificates.

Description

Daniel Bleichenbacher discovered that it might be possible to forge signatures signed by RSA keys with the exponent of 3. This affects a number of RSA signature implementations, including Mozilla's NSS.

Impact

Since several Certificate Authorities (CAs) are using an exponent of 3 it might be possible for an attacker to create a key with a false CA signature. This impacts any software using the NSS library, like the Mozilla products Firefox, Thunderbird and Seamonkey.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All NSS users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-libs/nss-3.11.3"

Note: As usual after updating a library, you should run 'revdep-rebuild' (from the app-portage/gentoolkit package) to ensure that all applications linked to it are properly rebuilt.

4. References

Updated October 17, 2006

Summary: This is a Gentoo Linux Security Advisory

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