CVE-2014-9862

What it actually does

Integer signedness error in bspatch.c triggers a heap-based buffer overflow when processing a malicious patch file, enabling arbitrary code execution or denial of service.

Why it matters to the business

Systems running affected older macOS versions could be compromised to run attacker code or rendered unavailable, risking data exposure and operational disruption; the vulnerability is long-public and no longer under active exploitation campaigns.

How an attack unfolds

An attacker crafts a specially formatted patch file that triggers the signedness miscalculation during bspatch processing; when the file is applied on a vulnerable system the overflow allows control of execution flow or memory corruption.

How to fix it

Upgrade affected Apple macOS installations to version 10.11.6 or later; replace any embedded bsdiff/bspatch components with patched equivalents in third-party products.

How to confirm the fix worked

Verify operating system version is 10.11.6 or newer; test bspatch against known-good and crafted patch files in a lab environment to confirm overflow is no longer possible.

Typical attack path

1. Craft malicious patch file exploiting integer signedness
2. Deliver file to target via email, download, or removable media
3. Induce victim or automated process to run bspatch on the file
4. Trigger heap overflow to achieve code execution or crash

How to detect it

Review system and application logs for bspatch invocations involving externally sourced patch files; inspect for crashes or unexpected memory allocations around patch application processes.

What your security team should do

• Inventory all macOS endpoints and confirm they are running 10.11.6 or later
• Block or sandbox execution of untrusted patch files in bspatch/bspatch-derived tools
• Monitor for any remaining legacy systems still using the vulnerable bsdiff implementation