CVE-2021-43947
📋 TL;DR
This vulnerability allows remote attackers with administrator privileges in Atlassian Jira Server and Data Center to execute arbitrary code via the Email Templates feature. It affects versions before 8.13.15 and from 8.14.0 before 8.20.3. This is a bypass of a previous security fix.
💻 Affected Systems
- Atlassian Jira Server
- Atlassian Jira Data Center
📦 What is this software?
Data Center by Atlassian
Jira by Atlassian
Jira Server by Atlassian
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the Jira instance and potentially the underlying server, leading to data theft, lateral movement, or ransomware deployment.
Likely Case
Administrator account compromise leading to unauthorized code execution, data manipulation, privilege escalation, and persistence within the Jira environment.
If Mitigated
Limited impact with proper network segmentation, strong access controls, and monitoring preventing successful exploitation even if vulnerable.
🎯 Exploit Status
Exploitation requires administrator credentials. The vulnerability bypasses a previous security fix (JSDSERVER-8665).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.13.15 or 8.20.3 and later
Vendor Advisory: https://jira.atlassian.com/browse/JRASERVER-73067
Restart Required: Yes
Instructions:
1. Backup your Jira instance and database. 2. Download the patched version (8.13.15 or 8.20.3+) from Atlassian. 3. Follow the official upgrade guide for your deployment type. 4. Restart the Jira service after upgrade.
🔧 Temporary Workarounds
Restrict Administrator Access
allLimit administrator accounts to only essential personnel and implement strong authentication controls.
Network Segmentation
allPlace Jira instances behind firewalls and restrict access to only trusted networks/IPs.
🧯 If You Can't Patch
- Immediately restrict all administrator account access and implement multi-factor authentication.
- Monitor Jira logs for suspicious administrator activity and implement network-based intrusion detection.
🔍 How to Verify
Check if Vulnerable:
Check your Jira version via the administration interface or by examining the Jira installation directory.Check Version:
On Linux: cat /path/to/jira/atlassian-jira/WEB-INF/classes/build.properties | grep versionVerify Fix Applied:
Confirm the Jira version is 8.13.15 or higher (if on 8.13.x branch) or 8.20.3 or higher (if on 8.14.x-8.20.x branch).📡 Detection & Monitoring
Log Indicators:
- Unusual administrator login patterns
- Suspicious modifications to email templates
- Unexpected process execution in Jira logs
Network Indicators:
- Unusual outbound connections from Jira server
- Suspicious HTTP requests to email template endpoints
SIEM Query:
source="jira.log" AND (event="admin_login" OR event="template_modify") AND user="suspicious_user"