Hashcash: Format string vulnerability

Background

Hashcash is a utility for generating Hashcash tokens, a proof-of-work system to reduce the impact of spam.

Description

Tavis Ormandy of the Gentoo Linux Security Audit Team identified a flaw in the Hashcash utility that an attacker could expose by specifying a malformed reply address.

Impact

Successful exploitation would permit an attacker to disrupt Hashcash users, and potentially execute arbitrary code.

Workaround

There is no known workaround at this time.

Resolution

All Hashcash users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-misc/hashcash-1.16-r1"