[ GLSA 200603-15 ] Crypt::CBC: Insecure initialization vector

[GLSA]

Gentoo Linux Security Advisory

Title: Crypt::CBC: Insecure initialization vector (GLSA 200603-15)
Severity: low
Exploitable: remote
Date: March 17, 2006
Bug(s): #126048
ID: 200603-15

Synopsis

Crypt::CBC uses an insecure initialization vector, potentially resulting in a weaker encryption.

Background

Crypt::CBC is a Perl module to encrypt data using cipher block chaining (CBC).

Affected Packages

Package: dev-perl/crypt-cbc
Vulnerable: < 2.17
Unaffected: >= 2.17
Architectures: All supported architectures


Description

Lincoln Stein discovered that Crypt::CBC fails to handle 16 bytes long initializiation vectors correctly when running in the RandomIV mode, resulting in a weaker encryption because the second part of every block will always be encrypted with zeros if the blocksize of the cipher is greater than 8 bytes.

Impact

An attacker could exploit weak ciphertext produced by Crypt::CBC to bypass certain security restrictions or to gain access to sensitive data.

Workaround

There is no known workaround at this time.

Resolution

All Crypt::CBC users should upgrade to the latest available version: