Ubuntu 12.04 LTS USN-1484-1 Moderate PyCrypto ElGamal Key Issue

ubuntu

June 28, 2012

PyCrypto improperly created ElGamal encryption keys.

Summary

PyCrypto improperly created ElGamal encryption keys.

Software Description:

- python-crypto: cryptographic algorithms and protocols for Python

Details:

It was discovered that PyCrypto produced inappropriate prime numbers when

generating ElGamal keys. An attacker could use this flaw to facilitate

brute-forcing of ElGamal encryption keys.

Topics Covered

security advisory moderate security update ubuntu brute-force attack python-crypto ElGamal key issue

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 12.04 LTS:
  python-crypto                   2.4.1-1ubuntu0.1

Ubuntu 11.10:
  python-crypto                   2.3-2ubuntu0.1

Ubuntu 11.04:
  python-crypto                   2.1.0-2ubuntu1.1

Ubuntu 10.04 LTS:
  python-crypto                   2.0.1+dfsg1-4ubuntu2.2

In general, a standard system update will make all the necessary changes.
If PyCrypto was used to generate ElGamal keys, we recommend they be
regenerated.