CVE-2025-27508
📋 TL;DR
The Emissary workflow engine's ChecksumCalculator class uses weak cryptographic algorithms (SHA-1, CRC32, SSDEEP) that are no longer considered secure. This vulnerability allows attackers to potentially forge checksums, manipulate data integrity, or bypass security controls when these algorithms are used in security-critical contexts. Users of Emissary versions before 8.24.0 are affected.
💻 Affected Systems
- Emissary
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers could forge checksums to bypass integrity checks, inject malicious data into workflows, or compromise data authenticity in security-critical applications.
Likely Case
Data integrity verification failures leading to incorrect workflow processing or data corruption in systems relying on these weak checksums.
If Mitigated
Limited impact if algorithms are only used for non-security purposes like basic data validation or performance optimization.
🎯 Exploit Status
Exploitation requires understanding of how checksums are used in specific deployments and ability to generate hash collisions or manipulate data.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.24.0
Vendor Advisory: https://github.com/NationalSecurityAgency/emissary/security/advisories/GHSA-hw43-fcmm-3m5g
Restart Required: No
Instructions:
1. Update Emissary to version 8.24.0 or later. 2. Review and update any custom code using ChecksumCalculator to ensure strong algorithms are specified. 3. Test workflow functionality after update.
🔧 Temporary Workarounds
Explicitly specify strong algorithms
allConfigure ChecksumCalculator to use only strong cryptographic algorithms (SHA-256, SHA-512) instead of default weak ones.
Configure algorithm parameter to 'SHA-256' or 'SHA-512' in all ChecksumCalculator calls
🧯 If You Can't Patch
- Audit all uses of ChecksumCalculator and ensure only strong algorithms are explicitly specified
- Implement additional integrity checks using strong algorithms alongside existing weak checksums
🔍 How to Verify
Check if Vulnerable:
Check Emissary version and review code for ChecksumCalculator usage with default or weak algorithm parameters.Check Version:
Check emissary version output or configuration files for version informationVerify Fix Applied:
Verify version is 8.24.0+ and confirm ChecksumCalculator calls specify strong algorithms or use updated defaults.📡 Detection & Monitoring
Log Indicators:
- Checksum validation failures
- Algorithm deprecation warnings
- Integrity check mismatches
Network Indicators:
- Unusual checksum patterns in data transfers
- Multiple checksum collisions
SIEM Query:
Search for checksum validation errors or algorithm deprecation warnings in application logs