CVE-2019-15796 python-apt downloads from untrusted sources

Medium 4.7 Published Updated

The python-apt library fails to verify repository signatures, allowing attackers to install malicious packages from unsigned sources.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
A user has to click or open something
Fix
Available

What is CVE-2019-15796?

CVE-2019-15796 is a medium-severity vulnerability in Canonical Python-apt, published on 26 Mar 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Python-apt doesn't check if hashes are signed in `Version.fetch_binary()` and `Version.fetch_source()` of apt/package.py or in `_fetch_archives()` of apt/cache.py in version 1.9.3ubuntu2 and earlier. This allows downloads from unsigned repositories which shouldn't be allowed and has been fixed in verisions 1.9.5, 1.9.0ubuntu1.2, 1.6.5ubuntu0.1, 1.1.0~beta1ubuntu0.16.04.7, 0.9.3.5ubuntu3+esm2, and 0.8.3ubuntu7.5.

Weakness: CWE-347, CWE-287

Which versions are affected by CVE-2019-15796?

10 open source packages ship an affected version, including python-apt. It affects 2 products.

PackageAffectedFixed in
python-apt PyPIAll versions0.8.3ubuntu7.5
python-apt PyPIAll versions0.8.3ubuntu7.5
python-apt PyPIFrom 0.9.00.9.3.5ubuntu3
python-apt PyPIFrom 0.9.00.9.3.5ubuntu3
python-apt PyPIFrom 1.2.01.6.5ubuntu0.1
python-apt PyPIFrom 1.2.01.6.5ubuntu0.1
4 more packages
python-apt PyPIFrom 1.7.01.9.0ubuntu1.2
python-apt PyPIFrom 1.7.01.9.0ubuntu1.2
python-apt PyPIFrom 1.9.11.9.5
python-apt PyPIFrom 1.9.11.9.5

Products include Debian Python-Apt, Ubuntu Python-Apt.

How do I fix CVE-2019-15796?

Upgrade python-apt to a fixed version for your release line: 0.8.3ubuntu7.5, 0.9.3.5ubuntu3, 1.6.5ubuntu0.1 or 1.9.0ubuntu1.2.

Is CVE-2019-15796 being exploited?

There is no known exploitation of CVE-2019-15796 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2019-15796, GHSA-pj65-3pf6-c5q4, UBUNTU-CVE-2019-15796.

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