CVE-2021-25758
📋 TL;DR
This vulnerability in JetBrains IntelliJ IDEA allows local code execution through insecure deserialization of workspace models. Attackers could exploit this to run arbitrary code on systems running vulnerable versions. Only users of IntelliJ IDEA before version 2020.3 are affected.
💻 Affected Systems
- JetBrains IntelliJ IDEA
📦 What is this software?
Intellij Idea by Jetbrains
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the local machine, potentially leading to data theft, lateral movement, or persistence establishment.
Likely Case
Local privilege escalation or arbitrary code execution within the user context, allowing access to sensitive files and development environments.
If Mitigated
Limited impact with proper network segmentation and user privilege restrictions, though local exploitation remains possible.
🎯 Exploit Status
Exploitation requires local access to the system. The vulnerability involves deserialization attacks which are well-understood attack vectors.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020.3 and later
Vendor Advisory: https://blog.jetbrains.com/blog/2021/02/03/jetbrains-security-bulletin-q4-2020/
Restart Required: Yes
Instructions:
1. Open IntelliJ IDEA. 2. Go to Help > Check for Updates. 3. Install version 2020.3 or later. 4. Restart IntelliJ IDEA after installation completes.
🔧 Temporary Workarounds
Restrict workspace file access
allLimit access to workspace files to prevent malicious deserialization
chmod 600 workspace.xml
Set file permissions to read/write only for owner
🧯 If You Can't Patch
- Restrict user privileges to minimize impact of potential code execution
- Implement application whitelisting to prevent execution of unauthorized binaries
🔍 How to Verify
Check if Vulnerable:
Check IntelliJ IDEA version in Help > About. If version is earlier than 2020.3, system is vulnerable.Check Version:
On Linux/macOS: grep -i 'version' ~/.IntelliJIdea*/config/options/ide.general.xml | head -1Verify Fix Applied:
Verify version is 2020.3 or later in Help > About. Test workspace loading functionality remains operational.📡 Detection & Monitoring
Log Indicators:
- Unusual process spawning from IntelliJ IDEA
- Errors in workspace deserialization logs
- Suspicious file access patterns
Network Indicators:
- Outbound connections from IntelliJ IDEA to unexpected destinations
SIEM Query:
process_name:"idea" AND (process_spawned:true OR file_access:"workspace.xml")