CVE-2024-9257

Executive Summary

CVE-2024-9257 is a high-severity vulnerability in the Logsign Unified SecOps Platform, specifically within the delete_gsuite_key_file endpoint. The flaw is a classic path traversal (CWE-22) issue, where the application fails to properly validate a user-supplied filename before using it in file deletion operations. An authenticated remote attacker can exploit this to delete arbitrary files within sensitive directories, potentially causing a denial of service or disrupting critical system functionality. The vulnerability was reported via the Zero Day Initiative (ZDI-CAN-25265) and currently has no known patch or public exploit code. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the impact is significant for affected deployments.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a proprietary software component of Logsign's platform.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
• Attack Vector: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: Low (PR:L) – Attacker needs valid credentials.
• User Interaction: None (UI:N) – No user action needed.
• Scope: Unchanged (S:U) – Vulnerability affects only the vulnerable component.
• Confidentiality Impact: None (C:N) – No data exposure.
• Integrity Impact: High (I:H) – Arbitrary file deletion can corrupt system state.
• Availability Impact: None (A:N) – Direct availability impact is not rated, but deletion of critical files can lead to denial of service.

Threat Level: Medium. While the CVSS score is moderate, the ability to delete arbitrary files in sensitive directories can lead to severe operational disruption. The requirement for authentication reduces the attack surface but does not eliminate risk.

Deep Dive & Mechanics

The vulnerability resides in the delete_gsuite_key_file endpoint of the Logsign Unified SecOps Platform. This endpoint is designed to allow authenticated administrators to delete G Suite key files used for integration. The flaw is a path traversal (CWE-22) caused by insufficient validation of the filename parameter.

Root Cause: The application does not sanitize or validate the user-supplied filename for path traversal sequences (e.g., ../). When the filename is passed to a file deletion function (e.g., unlink() or os.remove()), an attacker can manipulate the path to delete files outside the intended directory.

Attack Flow:

1. Attacker authenticates to the Logsign platform.
2. Attacker sends a crafted request to the delete_gsuite_key_file endpoint with a filename parameter containing path traversal sequences, such as ../../etc/passwd.
3. The application constructs a file path by concatenating a base directory (e.g., /var/logsign/gsuite_keys/) with the attacker-supplied filename.
4. The resulting path (e.g., /var/logsign/gsuite_keys/../../etc/passwd) resolves to /etc/passwd.
5. The application executes the file deletion operation, removing the targeted file.

Impact: An attacker can delete critical system files, configuration files, or application binaries, leading to denial of service, system instability, or privilege escalation. For example, deleting /etc/shadow could allow passwordless login, or deleting application binaries could crash the service.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on the vulnerability description.

Vulnerable Code (Python-like pseudocode):

@app.route('/delete_gsuite_key_file', methods=['POST'])
def delete_gsuite_key_file():
    filename = request.form['filename']
    base_path = '/var/logsign/gsuite_keys/'
    full_path = os.path.join(base_path, filename)
    if os.path.exists(full_path):
        os.remove(full_path)
        return "File deleted", 200
    else:
        return "File not found", 404

Patched Code (Hypothetical):

import os

@app.route('/delete_gsuite_key_file', methods=['POST'])
def delete_gsuite_key_file():
    filename = request.form['filename']
    base_path = '/var/logsign/gsuite_keys/'
    # Sanitize filename: remove path traversal sequences
    safe_filename = os.path.basename(filename)
    full_path = os.path.join(base_path, safe_filename)
    # Ensure the resolved path is within the base directory
    real_base = os.path.realpath(base_path)
    real_full = os.path.realpath(full_path)
    if not real_full.startswith(real_base):
        return "Invalid filename", 400
    if os.path.exists(real_full):
        os.remove(real_full)
        return "File deleted", 200
    else:
        return "File not found", 404

The patched version uses os.path.basename() to strip directory components and then verifies that the resolved path is within the intended base directory.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Valid credentials for the Logsign platform (e.g., admin user).
• Network access to the Logsign web interface.

Exploitation Steps:

1. Authenticate to the Logsign platform and obtain a session cookie.
2. Identify the delete_gsuite_key_file endpoint (e.g., via API documentation or fuzzing).
3. Craft a POST request with a malicious filename parameter.

Example Request (using cURL):

curl -X POST \
  -c cookies.txt -b cookies.txt \
  -d "filename=../../etc/passwd" \
  http://target/logsign/api/delete_gsuite_key_file

Expected Outcome: The /etc/passwd file is deleted, causing authentication issues or system instability.

Advanced Exploitation:

• Delete critical application files (e.g., /var/logsign/webapp.war) to cause denial of service.
• Delete configuration files (e.g., /etc/logsign/config.yaml) to disrupt logging or security monitoring.
• Chain with other vulnerabilities for privilege escalation.

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual file deletion events in system logs (e.g., auditd).
• Look for HTTP requests to the delete_gsuite_key_file endpoint with path traversal patterns (e.g., ../).
• Alert on deletion of critical system files (e.g., /etc/passwd, /etc/shadow).

Defense:

• Implement strict input validation on the filename parameter (allow only alphanumeric characters and dots).
• Use a whitelist of allowed filenames.
• Apply the principle of least privilege to the application user.
• Deploy a Web Application Firewall (WAF) to block path traversal attempts.
• Regularly backup critical files and configurations.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP POST requests to /delete_gsuite_key_file with filename parameter containing ../ or ..\\.
• Unusual file deletion events in server logs.

File System IOCs:

• Missing critical system files (e.g., /etc/passwd, /etc/shadow, /var/logsign/*).
• Unexpected empty directories in sensitive locations.

Log IOCs:

• Application logs showing deletion of files outside the expected gsuite_keys directory.
• System logs (e.g., audit.log) with unlink or remove operations on sensitive files.

Detection Engineering

YARA Rule

rule CVE_2024_9257_Logsign_File_Deletion {
    meta:
        description = "Detects path traversal attempts in Logsign delete_gsuite_key_file endpoint"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-9257"
    strings:
        $path_traversal = /\.\.\/|\.\.\\/
        $endpoint = "delete_gsuite_key_file"
    condition:
        $endpoint and $path_traversal
}

Sigma Rule

title: Logsign Arbitrary File Deletion via delete_gsuite_key_file
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects path traversal attempts in Logsign Unified SecOps Platform
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'delete_gsuite_key_file'
        cs-uri-query|contains: '../'
    condition: selection
falsepositives:
    - Legitimate use of relative paths (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-9257 Logsign Arbitrary File Deletion"; flow:to_server; content:"POST"; http_method; content:"delete_gsuite_key_file"; http_uri; content:"../"; http_client_body; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the endpoint: If possible, block access to the delete_gsuite_key_file endpoint via a WAF or reverse proxy until a patch is available.
2. Restrict access: Limit the endpoint to trusted IP addresses or require additional authentication (e.g., MFA).
3. Monitor logs: Enable detailed logging for file deletion operations and review for suspicious activity.

Long-term Fix:

• Apply the vendor patch once released.
• Implement input validation and path sanitization as shown in the patched code example.
• Conduct a security review of all file operation endpoints.

Workarounds:

• Use filesystem permissions to prevent the application user from deleting critical files.
• Deploy a file integrity monitoring (FIM) solution to alert on unauthorized deletions.

Valters IT