CVE-2021-41228
📋 TL;DR
TensorFlow's saved_model_cli tool is vulnerable to code injection via unsafe eval() calls on user-supplied strings, allowing attackers to execute arbitrary code on systems where the CLI tool runs. This affects TensorFlow versions before the patched releases. The impact is limited because the tool requires manual execution by users.
💻 Affected Systems
- TensorFlow
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full remote code execution with the privileges of the user running saved_model_cli, potentially leading to complete system compromise.
Likely Case
Limited code execution in controlled environments where users manually run the CLI with untrusted input, typically resulting in local privilege escalation or data exfiltration.
If Mitigated
No impact when using patched versions with safe flag enabled or when avoiding untrusted input to the CLI tool.
🎯 Exploit Status
Exploitation requires user interaction to run saved_model_cli with malicious input. Public proof-of-concept exists in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: TensorFlow 2.4.4, 2.5.2, 2.6.1, or 2.7.0
Vendor Advisory: https://github.com/tensorflow/tensorflow/security/advisories/GHSA-3rcw-9p9x-582v
Restart Required: No
Instructions:
1. Update TensorFlow to version 2.4.4, 2.5.2, 2.6.1, or 2.7.0. 2. Use pip install --upgrade tensorflow or conda update tensorflow. 3. Verify the safe flag defaults to True in saved_model_cli.
🔧 Temporary Workarounds
Avoid untrusted input to saved_model_cli
allDo not use saved_model_cli with untrusted or user-supplied strings in eval operations.
Use safe flag explicitly
allIf using a vulnerable version, explicitly set the safe flag to True when running saved_model_cli.
saved_model_cli ... --safe=True
🧯 If You Can't Patch
- Restrict access to saved_model_cli tool to trusted users only.
- Implement input validation and sanitization for any scripts that call saved_model_cli.
🔍 How to Verify
Check if Vulnerable:
Check TensorFlow version with 'python -c "import tensorflow as tf; print(tf.__version__)"' and compare to affected versions.Check Version:
python -c "import tensorflow as tf; print(tf.__version__)"Verify Fix Applied:
After updating, verify version is 2.4.4, 2.5.2, 2.6.1, or 2.7.0+ and test saved_model_cli with safe flag enabled.📡 Detection & Monitoring
Log Indicators:
- Unusual process execution from saved_model_cli with suspicious arguments
- Error logs containing eval-related failures in TensorFlow
Network Indicators:
- Not applicable - this is a local CLI tool vulnerability
SIEM Query:
Process execution where command_line contains 'saved_model_cli' and arguments contain suspicious strings like 'eval', 'exec', or 'import'🔗 References
- https://github.com/tensorflow/tensorflow/commit/8b202f08d52e8206af2bdb2112a62fafbc546ec7
- https://github.com/tensorflow/tensorflow/security/advisories/GHSA-3rcw-9p9x-582v
- https://github.com/tensorflow/tensorflow/commit/8b202f08d52e8206af2bdb2112a62fafbc546ec7
- https://github.com/tensorflow/tensorflow/security/advisories/GHSA-3rcw-9p9x-582v
