CVE-2023-53957
📋 TL;DR
Kimai 1.30.10 contains a SameSite cookie vulnerability that allows attackers to steal user session cookies through crafted PHP scripts. This enables session hijacking where attackers can impersonate legitimate users. All Kimai instances running version 1.30.10 are affected.
💻 Affected Systems
- Kimai
📦 What is this software?
Kimai by Kimai
⚠️ Risk & Real-World Impact
Worst Case
Complete account takeover, unauthorized access to sensitive time-tracking data, privilege escalation to administrative functions, and potential lateral movement within the organization.
Likely Case
Session hijacking leading to unauthorized access to user accounts, manipulation of time-tracking records, and exposure of sensitive project/client information.
If Mitigated
Limited impact with proper SameSite cookie settings, session validation, and network segmentation preventing successful exploitation.
🎯 Exploit Status
Exploit requires victim to execute malicious PHP script, which can be delivered via phishing or compromised websites.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.30.11 or later
Vendor Advisory: https://github.com/kimai/kimai/releases/tag/1.30.10
Restart Required: Yes
Instructions:
1. Backup your Kimai installation and database. 2. Download Kimai 1.30.11 or later from GitHub releases. 3. Replace the existing installation files with the new version. 4. Clear browser caches and restart web server services. 5. Verify the update by checking the version in Kimai interface.
🔧 Temporary Workarounds
Configure SameSite Cookie Settings
allManually configure SameSite cookie attributes to 'Strict' or 'Lax' in web server configuration or application settings.
For Apache: Header edit Set-Cookie ^(.*)$ "$1; SameSite=Strict"
For Nginx: add_header Set-Cookie "Path=/; HttpOnly; Secure; SameSite=Strict";
Implement Additional Session Validation
allAdd IP address validation and user-agent checking to session management.
Modify session handling code to validate $_SERVER['REMOTE_ADDR'] and $_SERVER['HTTP_USER_AGENT'] against stored session values.
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block suspicious cookie manipulation attempts.
- Isolate Kimai instance behind VPN or restrict access to trusted IP addresses only.
🔍 How to Verify
Check if Vulnerable:
Check Kimai version in admin interface or by examining the composer.json file for version 1.30.10.Check Version:
grep -r "version" composer.json | grep -o '[0-9]\+\.[0-9]\+\.[0-9]\+'Verify Fix Applied:
Verify version is 1.30.11 or later in admin interface and test that SameSite cookie attributes are properly set in browser developer tools.📡 Detection & Monitoring
Log Indicators:
- Unusual session creation patterns
- Multiple failed login attempts followed by successful login from different IP
- Access to session files from unexpected locations
Network Indicators:
- HTTP requests with manipulated cookie headers
- Traffic to known malicious domains hosting exploit scripts
- Unusual outbound connections from Kimai server
SIEM Query:
source="kimai_access.log" AND (cookie="*SameSite=None*" OR cookie="*SameSite=*" NOT cookie="*SameSite=Strict*")