[arch-security] [ASA-201601-24] python2-rsa: signature forgery

[Levente Polyak]

Arch Linux Security Advisory ASA-201601-24
==========================================

Severity: Medium
Date    : 2016-01-25
CVE-ID  : CVE-2016-1494
Package : python2-rsa
Type    : signature forgery
Remote  : Yes
Link    : https://wiki.archlinux.org/index.php/CVE

Summary
=======

The package python2-rsa before version 3.3-1 is vulnerable to signature
forgery.

Resolution
==========

Upgrade to 3.3-1.

# pacman -Syu "python2-rsa>=3.3-1"

The problem has been fixed upstream in version 3.3.

Workaround
==========

None.

Description
===========

The verify function in the RSA package for Python (Python-RSA) before
3.3 allows attackers to spoof signatures with a small public exponent
via crafted signature padding, aka a BERserk attack.

Impact
======

A remote attacker is able to spoof certain signatures via crafted
signature padding.

References
==========

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-1494
https://blog.filippo.io/bleichenbacher-06-signature-forgery-in-python-rsa/
https://bitbucket.org/sybren/python-rsa/pull-requests/14/security-fix-bb06-attack-in-verify-by/diff

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