CVE-2015-0245

What it actually does

D-Bus fails to validate the origin of ActivationFailure signals, permitting a local process to inject a forged signal during a race window before systemd replies, resulting in spurious activation failure errors returned to clients.

Why it matters to the business

Local users can repeatedly interrupt service activations on affected Linux systems, causing availability issues for applications that rely on D-Bus-activated services and increasing operational troubleshooting overhead.

How an attack unfolds

A local attacker identifies a service that D-Bus will activate, races to deliver a forged ActivationFailure signal before the legitimate systemd response arrives, and forces the activation request to fail without any authentication or elevated privileges.

How to fix it

Upgrade D-Bus to 1.6.30 or later, 1.8.16 or later, or 1.9.10 or later on all affected distributions; apply vendor patches for freedesktop dbus and openSUSE packages immediately.

How to confirm the fix worked

Verify installed D-Bus version is at or above the fixed releases; confirm absence of the signal-validation bypass by reviewing upstream commit history or running regression tests that exercise ActivationFailure paths.

Typical attack path

1. Locate a D-Bus-activated service
2. Time the sending of a crafted ActivationFailure signal ahead of the legitimate response
3. Observe the activation failure returned to the requesting client
4. Repeat to sustain denial of service

How to detect it

Inspect D-Bus daemon logs and systemd journal entries for repeated ActivationFailure signals originating from unexpected processes or occurring outside normal activation windows.

What your security team should do

• Prioritize patching D-Bus on all systems that expose D-Bus to untrusted local users
• Review service activation logs for anomalous failure patterns
• Restrict local user accounts where feasible until patches are deployed