CVE-2023-33551 – This CVE describes a heap buffer overflow vulne... (How to Fix)

Q: What is the severity of CVE-2023-33551?

CVE-2023-33551 has a CVSS score of 7.8 (HIGH). This CVE describes a heap buffer overflow vulnerability in erofs-utils v1.6 that allows remote attackers to execute arbitrary code by providing a maliciously crafted erofs filesystem image. Systems using erofs-utils v1.6 for filesystem operations are affected, particularly when processing untrusted filesystem images.

📋 TL;DR

This CVE describes a heap buffer overflow vulnerability in erofs-utils v1.6 that allows remote attackers to execute arbitrary code by providing a maliciously crafted erofs filesystem image. Systems using erofs-utils v1.6 for filesystem operations are affected, particularly when processing untrusted filesystem images.

💻 Affected Systems

Products:

erofs-utils

Versions: Version 1.6

Operating Systems: Linux distributions with erofs-utils v1.6

Default Config Vulnerable: ⚠️ Yes

Notes: Vulnerability triggers when processing crafted erofs filesystem images with the erofsfsck utility.

📦 What is this software?

Erofs Utils by Erofs Utils Project

View all CVEs affecting Erofs Utils →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution with the privileges of the erofsfsck process, potentially leading to full system compromise if the process runs with elevated privileges.

🟠

Likely Case

Denial of service through application crash, with potential for limited code execution depending on process privileges and exploit sophistication.

🟢

If Mitigated

Application crash without code execution if exploit fails or process runs with minimal privileges.

🌐 Internet-Facing: MEDIUM - Risk exists if systems process untrusted erofs images from external sources, but requires specific file processing scenarios.

🏢 Internal Only: LOW - Typically requires local access or specific file processing workflows to exploit.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires crafting a malicious erofs filesystem image and getting it processed by vulnerable systems.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Version 1.7 or later

Vendor Advisory: https://github.com/lometsj/blog_repo/issues/2

Restart Required: No

Instructions:

1. Update erofs-utils to version 1.7 or later using your distribution's package manager. 2. For Fedora: 'sudo dnf update erofs-utils'. 3. For other distributions, check package repositories for updated version.

🔧 Temporary Workarounds

Restrict erofsfsck usage

linux

Limit execution of erofsfsck to trusted users and avoid processing untrusted erofs images.

chmod 750 /usr/bin/erofsfsck
setfacl -m u:trusteduser:rx /usr/bin/erofsfsck

🧯 If You Can't Patch

Implement strict input validation for erofs filesystem images before processing
Run erofsfsck in a sandboxed environment with minimal privileges

🔍 How to Verify

Check if Vulnerable:

Check erofs-utils version: 'erofsfsck --version' or 'rpm -q erofs-utils' or 'dpkg -l erofs-utils'

Check Version:

erofsfsck --version

Verify Fix Applied:

Verify version is 1.7 or later: 'erofsfsck --version | grep -q "1\.7" && echo "Patched"'

📡 Detection & Monitoring

Log Indicators:

Segmentation fault or crash logs from erofsfsck process
Unexpected process termination of erofsfsck

Network Indicators:

Unusual file transfers of erofs images to vulnerable systems

SIEM Query:

process.name:"erofsfsck" AND (event.action:"segmentation_fault" OR event.action:"crash")

📊 Metadata

CVE ID: CVE-2023-33551

CVSS v3 Score: 7.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-787

Published: June 1, 2023

Last Updated: January 9, 2025

🔗 References

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