CVE-2020-5311 – CVE-2020-5311 is a buffer overflow vulnerabilit... (How to Fix)

Q: What is the severity of CVE-2020-5311?

CVE-2020-5311 has a CVSS score of 9.8 (CRITICAL). CVE-2020-5311 is a buffer overflow vulnerability in Pillow's SGI image decoding component. Attackers can exploit this by tricking users or systems into processing malicious SGI image files, potentially leading to remote code execution. This affects any application using vulnerable versions of the Pillow Python imaging library.

📋 TL;DR

CVE-2020-5311 is a buffer overflow vulnerability in Pillow's SGI image decoding component. Attackers can exploit this by tricking users or systems into processing malicious SGI image files, potentially leading to remote code execution. This affects any application using vulnerable versions of the Pillow Python imaging library.

💻 Affected Systems

Products:

Pillow (Python Imaging Library fork)

Versions: All versions before 6.2.2

Operating Systems: All operating systems where Pillow is installed

Default Config Vulnerable: ⚠️ Yes

Notes: Any Python application using Pillow to process SGI image files is vulnerable.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution with the privileges of the application processing the image, potentially leading to full system compromise.

🟠

Likely Case

Application crash (denial of service) or limited memory corruption leading to instability.

🟢

If Mitigated

Minimal impact if proper input validation and sandboxing prevent malicious file processing.

🌐 Internet-Facing: HIGH - Web applications processing user-uploaded images are directly exposed.

🏢 Internal Only: MEDIUM - Internal systems processing images from untrusted sources remain vulnerable.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires the victim to process a malicious SGI image file, which can be delivered via various vectors.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 6.2.2 and later

Vendor Advisory: https://github.com/python-pillow/Pillow/commit/a79b65c47c7dc6fe623aadf09aa6192fc54548f3

Restart Required: No

Instructions:

1. Update Pillow using pip: 'pip install --upgrade Pillow>=6.2.2'. 2. Verify the update with 'pip show Pillow'. 3. Restart any running Python applications using Pillow.

🔧 Temporary Workarounds

Disable SGI image support

all

Remove or disable SGI image decoding functionality in Pillow if not needed.

Not applicable - requires code modification to avoid SGI file processing

🧯 If You Can't Patch

Implement strict input validation to reject SGI image files from untrusted sources.
Run vulnerable applications in sandboxed environments with minimal privileges.

🔍 How to Verify

Check if Vulnerable:

Check Pillow version with 'python -c "import PIL; print(PIL.__version__)"' or 'pip show Pillow'.

Check Version:

python -c "import PIL; print(PIL.__version__)"

Verify Fix Applied:

Confirm version is 6.2.2 or higher using the same commands.

📡 Detection & Monitoring

Log Indicators:

Application crashes or abnormal terminations when processing image files
Memory access violation errors in logs

Network Indicators:

Unusual outbound connections from applications after image processing
Large or malformed image file uploads

SIEM Query:

source="application_logs" AND ("segmentation fault" OR "buffer overflow" OR "Pillow" OR "SGI")

📊 Metadata

CVE ID: CVE-2020-5311

CVSS v3 Score: 9.8 (CRITICAL)

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

CWE: CWE-120

Published: January 3, 2020

Last Updated: November 21, 2024

🔗 References

https://access.redhat.com/errata/RHSA-2020:0566 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0580 Third Party Advisory
https://github.com/python-pillow/Pillow/commit/a79b65c47c7dc6fe623aadf09aa6192fc54548f3 Patch,Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2MMU3WT2X64GS5WHDPKKC2WZA7UIIQ3A/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3DUMIBUYGJRAVJCTFUWBRLVQKOUTVX5P/
https://pillow.readthedocs.io/en/stable/releasenotes/6.2.2.html Release Notes,Third Party Advisory
https://usn.ubuntu.com/4272-1/ Third Party Advisory
https://www.debian.org/security/2020/dsa-4631 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0566 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0580 Third Party Advisory
https://github.com/python-pillow/Pillow/commit/a79b65c47c7dc6fe623aadf09aa6192fc54548f3 Patch,Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2MMU3WT2X64GS5WHDPKKC2WZA7UIIQ3A/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3DUMIBUYGJRAVJCTFUWBRLVQKOUTVX5P/
https://pillow.readthedocs.io/en/stable/releasenotes/6.2.2.html Release Notes,Third Party Advisory
https://usn.ubuntu.com/4272-1/ Third Party Advisory
https://www.debian.org/security/2020/dsa-4631 Third Party Advisory

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🔗 Related Vulnerabilities

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