CVE-2021-20400

Q: What is the severity of CVE-2021-20400?

CVE-2021-20400 has a CVSS score of 7.5 (HIGH). CVE-2021-20400 is a cryptographic weakness vulnerability in IBM QRadar SIEM where the software uses weaker-than-expected encryption algorithms. This allows attackers to potentially decrypt sensitive information stored or transmitted by the system. Affected users are those running IBM QRadar SIEM versions 7.3 and 7.4.

7.5 HIGH

📋 TL;DR

CVE-2021-20400 is a cryptographic weakness vulnerability in IBM QRadar SIEM where the software uses weaker-than-expected encryption algorithms. This allows attackers to potentially decrypt sensitive information stored or transmitted by the system. Affected users are those running IBM QRadar SIEM versions 7.3 and 7.4.

💻 Affected Systems

Products:

IBM QRadar SIEM

Versions: 7.3.0 through 7.3.3 and 7.4.0 through 7.4.3

Operating Systems: Linux

Default Config Vulnerable: ⚠️ Yes

Notes: All deployments using affected versions are vulnerable regardless of configuration.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Attackers decrypt highly sensitive security data, incident logs, and configuration information, potentially gaining full access to the SIEM system and all monitored environments.

🟠

Likely Case

Attackers decrypt specific sensitive information like credentials, API keys, or security event data stored in QRadar, leading to lateral movement or data exfiltration.

🟢

If Mitigated

With proper network segmentation and access controls, attackers cannot reach the vulnerable QRadar instance, limiting impact to isolated security monitoring data.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires access to encrypted data and cryptographic analysis capabilities.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 7.3.3 Patch 11 and 7.4.3 Patch 5

Vendor Advisory: https://www.ibm.com/support/pages/node/6520488

Restart Required: Yes

Instructions:

1. Download the appropriate patch from IBM Fix Central. 2. Apply patch using QRadar console. 3. Restart QRadar services. 4. Verify patch installation.

🔧 Temporary Workarounds

Network Segmentation

all

Restrict network access to QRadar instances to only trusted administrative networks.

Encryption Layer

all

Implement additional encryption layer for sensitive data stored in QRadar using stronger algorithms.

🧯 If You Can't Patch

Isolate QRadar instances from untrusted networks and internet access
Implement strict access controls and monitoring for QRadar administrative interfaces

🔍 How to Verify

Check if Vulnerable:

Check QRadar version via Admin interface or SSH: /opt/qradar/bin/qradar_manage -v

Check Version:

/opt/qradar/bin/qradar_manage -v

Verify Fix Applied:

Verify patch installation in QRadar Admin interface under System & License Management > Updates

📡 Detection & Monitoring

Log Indicators:

Unusual cryptographic operations in QRadar logs
Multiple failed decryption attempts

Network Indicators:

Unusual traffic patterns to/from QRadar encryption endpoints
Traffic analysis tools detecting weak cipher usage

SIEM Query:

source="qradar" AND (event="cryptographic_error" OR event="decryption_failure")

📊 Metadata

CVE ID: CVE-2021-20400

CVSS v3 Score: 7.5 (HIGH)

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

CWE: CWE-326

Published: December 1, 2021

Last Updated: November 21, 2024

🔗 References

https://exchange.xforce.ibmcloud.com/vulnerabilities/196074 VDB Entry,Vendor Advisory
https://www.ibm.com/support/pages/node/6520488 Patch,Vendor Advisory
https://exchange.xforce.ibmcloud.com/vulnerabilities/196074 VDB Entry,Vendor Advisory
https://www.ibm.com/support/pages/node/6520488 Patch,Vendor Advisory

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

Qradar Security Information And Event Manager by Ibm

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Network Segmentation

Encryption Layer

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

🔗 Related Vulnerabilities