CVE-2024-7340: Weave Server Path Traversal Vulnerability

CVE-2024-7340 Overview

CVE-2024-7340 is a path traversal vulnerability in the Weave server API that allows remote users to fetch files from a specific directory. Due to a lack of input validation, attackers can traverse directory structures and leak arbitrary files remotely. In various common scenarios, this allows a low-privileged user to assume the role of the server admin, significantly escalating their privileges within the system.

Critical Impact

Remote attackers with low-level access can exploit this path traversal flaw to read sensitive files and potentially escalate privileges to server administrator level.

Affected Products

• Weave Server (Weights & Biases)
• wandb/weave package versions prior to patch

Discovery Timeline

• 2024-07-31 - CVE-2024-7340 published to NVD
• 2024-11-25 - Last updated in NVD database

Technical Details for CVE-2024-7340

Vulnerability Analysis

This vulnerability stems from insufficient input validation in the Weave server API's file retrieval functionality. The API is designed to allow remote users to fetch files from a designated directory, but fails to properly sanitize user-supplied input for path traversal sequences such as ../. This improper input validation (CWE-20) combined with the path traversal weakness (CWE-22) enables attackers to escape the intended directory constraints and access arbitrary files on the server filesystem.

The network-accessible nature of this vulnerability means that any authenticated user with low-level privileges can potentially exploit it without requiring any user interaction. The successful exploitation results in high impact to confidentiality, integrity, and availability, as sensitive configuration files, credentials, and system data may be exposed, potentially allowing the attacker to assume administrative control of the server.

Root Cause

The root cause is improper input validation (CWE-20) combined with path traversal (CWE-22) in the file retrieval functionality. The Weave server API does not adequately sanitize file path parameters, allowing directory traversal sequences to bypass intended access restrictions. When processing file requests, the application concatenates user-supplied input directly into file system paths without validating that the resulting path stays within the allowed directory boundary.

Attack Vector

The attack is executed over the network by an authenticated user with minimal privileges. An attacker sends crafted API requests containing path traversal sequences (e.g., ../../../etc/passwd or similar patterns) to the file retrieval endpoint. Since the server fails to validate and normalize the requested path, it follows the traversal sequences and returns files outside the designated directory.

The exploitation chain typically involves:

1. Authenticating to the Weave server with a low-privilege account
2. Identifying the vulnerable file retrieval API endpoint
3. Crafting malicious requests with path traversal payloads
4. Retrieving sensitive files such as configuration files, API keys, or authentication tokens
5. Using obtained credentials or secrets to escalate privileges to server administrator

For technical details on the vulnerability mechanism, refer to the JFrog Vulnerability Report.

Detection Methods for CVE-2024-7340

Indicators of Compromise

• Unusual file access patterns in server logs, particularly requests containing ../ sequences
• API requests targeting paths outside the expected directory structure
• Unexpected access to sensitive system files like /etc/passwd, configuration files, or credential stores
• Authentication anomalies or privilege escalation events following file access attempts

Detection Strategies

• Monitor web server and application logs for path traversal patterns including ../, ..\, %2e%2e%2f, and URL-encoded variants
• Implement Web Application Firewall (WAF) rules to detect and block path traversal attempts in API requests
• Deploy file integrity monitoring on sensitive directories to detect unauthorized read access
• Utilize SentinelOne Singularity XDR to detect suspicious file access patterns and potential exploitation activity

Monitoring Recommendations

• Enable verbose logging on the Weave server API to capture detailed request information
• Configure alerts for any file access outside designated directories
• Monitor for sudden changes in user privilege levels that may indicate successful exploitation
• Review authentication logs for anomalous login patterns following potential exploitation attempts

How to Mitigate CVE-2024-7340

Immediate Actions Required

• Update Weave server to the latest patched version immediately
• Review access logs for signs of exploitation attempts or successful attacks
• Audit user accounts for any unauthorized privilege escalations
• Implement network segmentation to limit exposure of the Weave server API
• Rotate any credentials or API keys that may have been exposed

Patch Information

The vulnerability has been addressed by the Weights & Biases team. The fix is available in the GitHub Pull Request #1657. Organizations should update their Weave server installation to incorporate this security patch. Review the JFrog Vulnerability Report for additional technical details and remediation guidance.

Workarounds

• Implement strict input validation at the network perimeter using WAF rules to block path traversal patterns
• Restrict network access to the Weave server API to trusted IP ranges only
• Run the Weave server in a containerized environment with limited filesystem access
• Apply principle of least privilege to the Weave server process, limiting its ability to read sensitive system files

# Example WAF rule to block path traversal attempts
# Add to your reverse proxy or WAF configuration
SecRule REQUEST_URI "@rx \.\./" "id:1001,phase:1,deny,status:403,msg:'Path Traversal Attempt'"
SecRule REQUEST_URI "@rx %2e%2e%2f" "id:1002,phase:1,deny,status:403,msg:'Encoded Path Traversal Attempt'"