CVE-2021-31292 – This CVE describes an integer overflow vulnerab... (How to Fix)

Q: What is the severity of CVE-2021-31292?

CVE-2021-31292 has a CVSS score of 7.5 (HIGH). This CVE describes an integer overflow vulnerability in Exiv2's CrwMap::encode0x1810 function that allows attackers to trigger a heap-based buffer overflow via crafted metadata. Attackers can cause denial of service (crash) by exploiting this vulnerability. Any system or application using Exiv2 0.27.3 to process image metadata is potentially affected.

📋 TL;DR

This CVE describes an integer overflow vulnerability in Exiv2's CrwMap::encode0x1810 function that allows attackers to trigger a heap-based buffer overflow via crafted metadata. Attackers can cause denial of service (crash) by exploiting this vulnerability. Any system or application using Exiv2 0.27.3 to process image metadata is potentially affected.

💻 Affected Systems

Products:

Exiv2

Versions: 0.27.3 and possibly earlier versions

Operating Systems: Linux, Windows, macOS - any OS running vulnerable Exiv2

Default Config Vulnerable: ⚠️ Yes

Notes: Any application or service that uses Exiv2 library to process image metadata (CRW files specifically) is vulnerable

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise if combined with other vulnerabilities, though CVSS indicates only DoS impact

🟠

Likely Case

Denial of service through application crash when processing malicious image files

🟢

If Mitigated

Application crash with no further impact if proper sandboxing and privilege separation are implemented

🌐 Internet-Facing: MEDIUM - Exploitation requires processing malicious files, which could occur through file uploads or web services

🏢 Internal Only: LOW - Requires user interaction to process malicious files, less likely in controlled environments

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires crafting malicious metadata in image files; public references show proof-of-concept details

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 0.27.4 and later

Vendor Advisory: https://github.com/Exiv2/exiv2/issues/1530

Restart Required: Yes

Instructions:

1. Update Exiv2 to version 0.27.4 or later. 2. For Linux distributions, use package manager: 'sudo apt update && sudo apt upgrade exiv2' (Debian/Ubuntu) or 'sudo yum update exiv2' (RHEL/CentOS). 3. Restart any services using Exiv2 library.

🔧 Temporary Workarounds

Disable CRW file processing

all

Configure applications to reject or not process CRW (Canon Raw) image files

Application-specific configuration required

Input validation for image files

all

Implement file type validation and size limits for image uploads

🧯 If You Can't Patch

Implement network segmentation to isolate systems using Exiv2
Use application sandboxing or containerization to limit impact of potential crashes

🔍 How to Verify

Check if Vulnerable:

Check Exiv2 version: 'exiv2 --version' or 'dpkg -l | grep exiv2' or 'rpm -qa | grep exiv2'

Check Version:

exiv2 --version

Verify Fix Applied:

Verify version is 0.27.4 or later: 'exiv2 --version | grep -q "0\.27\.[4-9]\|0\.2[8-9]\|0\.[3-9]" && echo "Patched"'

📡 Detection & Monitoring

Log Indicators:

Application crashes with segmentation faults when processing image files
Error logs mentioning Exiv2 or metadata parsing failures

Network Indicators:

Unusual image file uploads to web services
Multiple failed image processing attempts

SIEM Query:

source="application.log" AND ("segmentation fault" OR "SIGSEGV") AND ("exiv2" OR "metadata" OR "image processing")

📊 Metadata

CVE ID: CVE-2021-31292

CVSS v3 Score: 7.5 (HIGH)

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

CWE: CWE-190

Published: July 26, 2021

Last Updated: November 21, 2024

🔗 References

https://github.com/Exiv2/exiv2/issues/1530 Exploit,Issue Tracking,Patch,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/08/msg00028.html Mailing List,Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMDT4PJB7P43WSOM3TRQIY3J33BAFVVE/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UYGDELIFFJWKUU7SO3QATCIXCZJERGAC/
https://security.gentoo.org/glsa/202312-06
https://www.debian.org/security/2021/dsa-4958 Third Party Advisory
https://github.com/Exiv2/exiv2/issues/1530 Exploit,Issue Tracking,Patch,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/08/msg00028.html Mailing List,Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMDT4PJB7P43WSOM3TRQIY3J33BAFVVE/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UYGDELIFFJWKUU7SO3QATCIXCZJERGAC/
https://security.gentoo.org/glsa/202312-06
https://www.debian.org/security/2021/dsa-4958 Third Party Advisory

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