CVE-2015-0247

What it actually does

Heap-based buffer overflow in libext2fs openfs.c allows local code execution when processing a filesystem image containing crafted block group descriptor data.

Why it matters to the business

Attackers with local access can run arbitrary code on affected systems, potentially leading to privilege escalation or persistence on servers and workstations that process untrusted filesystem images.

How an attack unfolds

An attacker creates a malicious filesystem image with oversized or malformed block group descriptors, then causes a local process using the vulnerable libext2fs library to parse the image, triggering the heap overflow and executing attacker-supplied code.

How to fix it

Upgrade e2fsprogs to version 1.42.12 or later. For humhub/humhub (GIT) apply the fix in commit fbcfcbbb4469542d6730fd069c8d2e42ac2bed2e.

How to confirm the fix worked

Verify e2fsprogs version is 1.42.12 or newer; confirm humhub/humhub instances are at commit fbcfcbbb4469542d6730fd069c8d2e42ac2bed2e or later; test with crafted images in isolated environments.

Typical attack path

1. Obtain local user access on target system
2. Craft malicious ext2/ext3/ext4 filesystem image with corrupted block group descriptors
3. Trigger processing of the image via mount, fsck, or application using libext2fs
4. Exploit resulting heap overflow to execute arbitrary code

How to detect it

Review system logs for unexpected execution of e2fsck, dumpe2fs, or mount operations on non-standard images; monitor for new processes spawned after filesystem operations by unprivileged users.

What your security team should do

• Prioritize patching systems that mount or inspect untrusted filesystem images
• Remove or restrict local user accounts on high-value systems until updated
• Scan for older e2fsprogs packages across the environment