Opera: RSA signature forgery

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200609-18 / opera
Release Date	September 28, 2006
Latest Revision	September 28, 2006: 02
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
www-client/opera	< 9.02	>= 9.02	All supported architectures

Related bugreports: #147838

Synopsis

Opera fails to correctly verify certain signatures.

2. Impact Information

Background

Opera is a multi-platform web browser.

Description

Opera makes use of OpenSSL, which fails to correctly verify PKCS #1 v1.5 RSA signatures signed by a key with exponent 3. Some CAs in Opera's list of trusted signers are using root certificates with exponent 3.

Impact

An attacker could forge certificates which will appear valid and signed by a trusted CA.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All Opera users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=www-client/opera-9.02"

4. References

Page updated September 28, 2006

Summary: This is a Gentoo Linux Security Advisory

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