CVE-2021-32950 – This vulnerability allows attackers to cause de... (How to Fix)

Q: What is the severity of CVE-2021-32950?

CVE-2021-32950 has a CVSS score of 7.1 (HIGH). This vulnerability allows attackers to cause denial-of-service or read sensitive memory information by exploiting an out-of-bounds read issue in the Drawings SDK when parsing malicious DXF files. It affects all versions of Siemens Drawings SDK prior to 2022.4. Organizations using Siemens industrial software that incorporates this SDK are at risk.

📋 TL;DR

This vulnerability allows attackers to cause denial-of-service or read sensitive memory information by exploiting an out-of-bounds read issue in the Drawings SDK when parsing malicious DXF files. It affects all versions of Siemens Drawings SDK prior to 2022.4. Organizations using Siemens industrial software that incorporates this SDK are at risk.

💻 Affected Systems

Products:

Siemens Drawings SDK
Siemens products incorporating Drawings SDK

Versions: All versions prior to 2022.4

Operating Systems: Windows, Linux, Other platforms using the SDK

Default Config Vulnerable: ⚠️ Yes

Notes: Affects any application using the vulnerable Drawings SDK to parse DXF files. Siemens products like COMOS, SIMATIC PCS 7, and others may be impacted.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Attackers could read sensitive information from memory, potentially exposing credentials, configuration data, or other critical system information, leading to further compromise of industrial control systems.

🟠

Likely Case

Denial-of-service conditions disrupting industrial operations by crashing applications that process DXF files, potentially affecting production systems.

🟢

If Mitigated

Limited impact with proper network segmentation, file validation, and updated software preventing exploitation attempts.

🌐 Internet-Facing: MEDIUM - Systems directly exposed to untrusted DXF files from external sources are at risk, but exploitation requires file processing capability.

🏢 Internal Only: MEDIUM - Internal systems processing DXF files from potentially compromised sources or malicious insiders could be affected.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires the target to process a malicious DXF file. No public exploit code is known, but the vulnerability is documented in multiple advisories.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 2022.4 or later

Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-155599.pdf

Restart Required: Yes

Instructions:

1. Identify affected Siemens products using Drawings SDK. 2. Update to Drawings SDK version 2022.4 or later. 3. Apply vendor-specific patches for Siemens products. 4. Restart affected applications/services.

🔧 Temporary Workarounds

Restrict DXF file processing

all

Limit processing of DXF files to trusted sources and implement file validation.

Network segmentation

all

Isolate systems using Drawings SDK from untrusted networks.

🧯 If You Can't Patch

Implement strict file upload controls and validation for DXF files
Monitor systems for crashes or unusual behavior when processing DXF files

🔍 How to Verify

Check if Vulnerable:

Check Siemens product documentation or use vendor tools to identify Drawings SDK version. Versions prior to 2022.4 are vulnerable.

Check Version:

Consult Siemens product documentation for version checking commands specific to each product.

Verify Fix Applied:

Verify Drawings SDK version is 2022.4 or later and confirm no Siemens security advisories indicate remaining vulnerability.

📡 Detection & Monitoring

Log Indicators:

Application crashes when processing DXF files
Unusual memory access errors in application logs

Network Indicators:

Unexpected DXF file transfers to industrial systems
File uploads to systems using Drawings SDK

SIEM Query:

source="application_logs" AND (event="crash" OR event="memory_error") AND file_type="dxf"

📊 Metadata

CVE ID: CVE-2021-32950

CVSS v3 Score: 7.1 (HIGH)

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

CWE: CWE-125

Published: June 17, 2021

Last Updated: November 21, 2024

🔗 References

https://cert-portal.siemens.com/productcert/pdf/ssa-155599.pdf Patch,Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-365397.pdf Patch,Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-159-02 Third Party Advisory,US Government Resource
https://www.zerodayinitiative.com/advisories/ZDI-21-988/ Third Party Advisory,VDB Entry
https://cert-portal.siemens.com/productcert/pdf/ssa-155599.pdf Patch,Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-365397.pdf Patch,Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-159-02 Third Party Advisory,US Government Resource
https://www.zerodayinitiative.com/advisories/ZDI-21-988/ Third Party Advisory,VDB Entry

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2021-32950, you might also want to check these: