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Hashcash: Possible heap overflow


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200606-25 / hashcash
Release Date June 26, 2006
Latest Revision July 29, 2006: 02
Impact high
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
net-misc/hashcash < 1.21 >= 1.21 All supported architectures

Related bugreports: #134960


A heap overflow vulnerability in the Hashcash utility could allow an attacker to execute arbitrary code.

2.  Impact Information


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


Andreas Seltenreich has reported a possible heap overflow in the array_push() function in hashcash.c, as a result of an incorrect amount of allocated memory for the "ARRAY" structure.


By sending malicious entries to the Hashcash utility, an attacker may be able to cause an overflow, potentially resulting in the execution of arbitrary code with the privileges of the user running the application.

3.  Resolution Information


There is no known workaround at this time.


All Hashcash users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/hashcash-1.21"

4.  References


Page updated June 26, 2006

Summary: This is a Gentoo Linux Security Advisory

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