CVE-2021-26068
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Atlassian Jira Server instances with the Slack plugin installed via a template injection flaw. Attackers can exploit this to gain full control of affected systems. Organizations running vulnerable versions of the Jira Server for Slack plugin are affected.
💻 Affected Systems
- Atlassian Jira Server for Slack plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary commands, steal sensitive data, install malware, pivot to other systems, and maintain persistent access.
Likely Case
Remote code execution leading to data exfiltration, credential theft, and potential lateral movement within the network.
If Mitigated
Limited impact if proper network segmentation, least privilege access, and monitoring are in place, though exploitation could still occur.
🎯 Exploit Status
Template injection vulnerabilities are often easily weaponized. Public exploit code exists for similar vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.0.15 and later
Vendor Advisory: https://confluence.atlassian.com/jira/jira-server-for-slack-security-advisory-17th-february-2021-1044091690.html
Restart Required: Yes
Instructions:
1. Log into Jira Server as administrator. 2. Navigate to Manage apps > Manage apps. 3. Find Jira Server for Slack plugin. 4. Update to version 2.0.15 or later. 5. Restart Jira Server.
🔧 Temporary Workarounds
Disable Slack plugin
allTemporarily disable the vulnerable plugin until patching can be completed
Network isolation
allRestrict network access to Jira Server to trusted IPs only
🧯 If You Can't Patch
- Immediately disable the Jira Server for Slack plugin
- Implement strict network access controls and monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Jira Server plugin version: Admin > Manage apps > Manage apps > Jira Server for Slack pluginCheck Version:
Check via Jira web interface or plugin manifest filesVerify Fix Applied:
Verify plugin version is 2.0.15 or higher in the Manage apps section📡 Detection & Monitoring
Log Indicators:
- Unusual template processing errors
- Suspicious HTTP requests to Slack plugin endpoints
- Unexpected process execution from Jira context
Network Indicators:
- HTTP requests to /rest/slack/1.0/* endpoints with unusual parameters
- Outbound connections from Jira to unexpected destinations
SIEM Query:
source="jira.log" AND ("slack" OR "/rest/slack/") AND (error OR exception OR "template")