CVE-2024-1481

Executive Summary

CVE-2024-1481 is a vulnerability in FreeIPA that allows a remote attacker to craft an HTTP request with parameters that can be interpreted as command arguments to kinit on the FreeIPA server. This can lead to a denial of service (DoS) condition. The vulnerability is classified under CWE-88 (Improper Neutralization of Argument Delimiters in a Command). No public proof-of-concept (PoC) or exploit code is currently available, and the patch status is unknown. The attack vector is remote, and the complexity is low, requiring no authentication.

CVSS Breakdown & Threat Level

The CVSS score is 0.0, indicating that no official CVSS vector has been assigned. However, based on the description, the vulnerability is likely to have a high availability impact. The attack vector is network-based, with low attack complexity and no privileges required. The threat level is considered medium due to the potential for denial of service.

Deep Dive & Mechanics

The vulnerability exists in the FreeIPA web interface, which processes HTTP requests. An attacker can craft a request with parameters that are not properly sanitized. These parameters are then passed to the kinit command, which is used for Kerberos authentication. By injecting command arguments, the attacker can cause kinit to behave unexpectedly, leading to a crash or resource exhaustion, resulting in a denial of service.

The core issue is improper input validation. The application does not neutralize argument delimiters (e.g., spaces, quotes) before passing user-supplied data to the command line. This allows an attacker to inject additional arguments that alter the behavior of kinit.

Vulnerable vs. Patched Code

No specific vulnerable or patched code is available. The vulnerability is in the HTTP request handling logic of FreeIPA. A patched version would likely include input sanitization to prevent the injection of command arguments. For example, the vulnerable code might look like:

# Vulnerable: Directly using user input in command
import subprocess
user_input = request.GET.get('param')
subprocess.run(['kinit', user_input])

A patched version would sanitize the input:

# Patched: Sanitize input to prevent argument injection
import subprocess
import shlex
user_input = request.GET.get('param')
safe_input = shlex.quote(user_input)
subprocess.run(['kinit', safe_input])

Exploitation & Lab Setup

Red Team

To exploit this vulnerability, an attacker would send a crafted HTTP request to the FreeIPA server. For example:

curl "http://target-freeipa-server/endpoint?param=--help"

This could cause kinit to display help text instead of performing authentication, potentially leading to a denial of service. More sophisticated attacks could use parameters that cause kinit to hang or crash.

Blue Team

To detect exploitation attempts, monitor HTTP logs for unusual parameters. Look for requests containing command-line flags (e.g., --help, -v, --version) in parameters that are passed to kinit. Also, monitor system logs for abnormal kinit behavior, such as unexpected crashes or resource usage.

Indicators of Compromise (IOCs)

• HTTP requests with parameters containing command-line flags (e.g., --help, -v, --version)
• System logs showing kinit crashes or unexpected behavior
• High CPU or memory usage by kinit processes
• Unusual network traffic to the FreeIPA server

Detection Engineering

YARA Rule

rule CVE_2024_1481_FreeIPA_DoS {
    meta:
        description = "Detects HTTP requests with potential kinit argument injection"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-1481"
    strings:
        $flag1 = "--help" nocase
        $flag2 = "-v" nocase
        $flag3 = "--version" nocase
        $flag4 = "-h" nocase
    condition:
        any of ($flag*) and filesize < 10KB
}

Sigma Rule

title: CVE-2024-1481 FreeIPA kinit Argument Injection
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects HTTP requests with potential kinit argument injection
author: Valters IT
date: 2024/01/01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains:
            - '--help'
            - '-v'
            - '--version'
            - '-h'
    condition: selection
falsepositives:
    - Legitimate use of help parameters
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-1481 FreeIPA kinit Argument Injection"; flow:to_server; content:"--help"; http_uri; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

• Patch: Apply any available patches from FreeIPA. If no patch is available, consider upgrading to a version that includes input sanitization.
• Workaround: Implement input validation on the web server to block requests containing command-line flags in parameters.
• Network: Use a web application firewall (WAF) to filter malicious requests.
• Monitoring: Enable logging and monitoring for abnormal kinit behavior.

Valters IT
Securing Digital Frontiers