CVE-2014-0487

What it actually does

APT fails to perform signature verification on package files when an If-Modified-Since header indicates the file has not changed, allowing a modified package to be accepted without integrity checks.

Why it matters to the business

Organizations using older Debian package management could install tampered software updates, leading to system compromise, data exposure, or unauthorized code execution across fleets of servers and workstations; the issue has been public since 2014 with no active exploitation campaigns noted.

How an attack unfolds

An attacker positioned as a package mirror or performing a man-in-the-middle attack responds to an apt-get update request with a package file whose content has been altered yet includes an If-Modified-Since header that tricks APT into skipping its normal verification step, resulting in installation of malicious code.

How to fix it

Upgrade Advanced Package Tool (APT) to version 1.0.9 or later on all affected Debian-based systems; enable package verification settings and consider pinning repositories to trusted mirrors.

How to confirm the fix worked

Confirm APT version is 1.0.9 or newer via apt --version; test by attempting an update against a controlled mirror that returns modified content with If-Modified-Since and verify that the package is rejected.

Typical attack path

1. Attacker compromises or impersonates a software repository or network path used by apt
2. Victim system runs apt update or apt-get install
3. Attacker returns a tampered .deb with an If-Modified-Since header
4. APT skips signature verification due to the header
5. Malicious package is installed and executed

How to detect it

Review apt history logs in /var/log/apt/ for entries showing package downloads that bypassed verification; look for unexpected changes to installed packages or binaries shortly after update operations.

What your security team should do

• Immediately inventory all systems running APT versions prior to 1.0.9
• Prioritize patching production package-management hosts within 30 days
• Implement network controls to restrict package downloads to known-good repositories
• Add monitoring for unexpected package installations or changes to /var/lib/apt