CVE-2015-0840

What it actually does

The flaw permits crafted Debian source control (.dsc) files to bypass signature verification checks performed by dpkg-source, allowing unsigned or improperly signed package metadata to be processed as valid.

Why it matters to the business

Organizations relying on Debian or Ubuntu package workflows face risk of tampered source packages being accepted, which can lead to supply-chain compromise, delayed patching, and increased operational overhead to audit package sources.

How an attack unfolds

An attacker prepares a malicious .dsc file with manipulated signature fields, distributes it through repositories or direct channels, and relies on the victim running dpkg-source to extract or build the package, causing the tool to skip verification and accept the untrusted content.

How to fix it

Upgrade dpkg to version 1.16.16 or later on affected Debian releases and to 1.17.25 or later on 1.17.x branches; Ubuntu users should apply the corresponding security updates for their release. Rebuild or re-verify any packages previously processed with vulnerable dpkg-source versions.

How to confirm the fix worked

Confirm installed dpkg version meets or exceeds the fixed releases listed in the advisory; test signature verification behavior against known-good and crafted .dsc files after upgrade.

Typical attack path

1. Craft a .dsc file containing invalid or missing signature data that exploits parsing weaknesses
2. Host or distribute the file via public repositories, mirrors, or direct delivery
3. Trick or wait for administrators to invoke dpkg-source on the file during package extraction or build
4. Gain execution or injection of unauthorized package contents into the build environment

How to detect it

Review build logs and package processing history for invocations of dpkg-source on externally obtained .dsc files; look for packages that were extracted or built without corresponding signature validation entries in audit trails.

What your security team should do

• Prioritize patching dpkg on all build and packaging systems within 30 days given the age of the disclosure
• Audit internal package build pipelines for use of dpkg-source and enforce signature verification policies
• Monitor upstream Debian and Ubuntu security feeds for any related package updates