Kod programskog paketa apt uočen je sigurnosni propust koji zlonamjernim korisnicima omogućuje pokretanje MITM (eng. man-in-the-middle) napada.

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Ubuntu Security Notice USN-1215-1
September 22, 2011

apt vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 11.04
- Ubuntu 10.10
- Ubuntu 10.04 LTS
- Ubuntu 8.04 LTS

Summary:

An attacker could trick APT into installing altered packages.

Software Description:
- apt: Advanced front-end for dpkg

Details:

It was discovered that the apt-key utility incorrectly verified GPG
keys when downloaded via the net-update option. If a remote attacker were
able to perform a man-in-the-middle attack, this flaw could potentially be
used to install altered packages. This update corrects the issue by
disabling the net-update option completely. A future update will re-enable
the option with corrected verification.

Update instructions:

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

Ubuntu 11.04:
  apt                             0.8.13.2ubuntu4.2

Ubuntu 10.10:
  apt                             0.8.3ubuntu7.2

Ubuntu 10.04 LTS:
  apt                             0.7.25.3ubuntu9.7

Ubuntu 8.04 LTS:
  apt                             0.7.9ubuntu17.3

In general, a standard system update will make all the necessary changes.

References:
  http://www.ubuntu.com/usn/usn-1215-1
  https://launchpad.net/bugs/856489

Package Information:
  https://launchpad.net/ubuntu/+source/apt/0.8.13.2ubuntu4.2
  https://launchpad.net/ubuntu/+source/apt/0.8.3ubuntu7.2
  https://launchpad.net/ubuntu/+source/apt/0.7.25.3ubuntu9.7
  https://launchpad.net/ubuntu/+source/apt/0.7.9ubuntu17.3