Overview

This report covers a critical vulnerability in the Apache::AuthAny::Cookie module for Perl. The flaw lies in the insecure generation of session ids, which could be leveraged by an attacker to gain unauthorized access to systems. Anyone using version 0.201 or earlier of this module is vulnerable, and due to the potential for system compromise or data leakage, it is crucial that this issue is addressed promptly.

Vulnerability Summary

CVE ID: CVE-2025-40933
Severity: High (7.5)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Apache::AuthAny::Cookie for Perl | 0.201 or earlier

How the Exploit Works

An attacker can exploit this vulnerability by predicting the session ids generated by the module. The module generates these ids using an MD5 hash of the epoch time and a call to the built-in rand function. The epoch time may be guessed, especially if leaked from the HTTP Date header. The built-in rand function is not cryptographically secure, making this process even more vulnerable. Predictable session ids could allow an attacker to hijack sessions and gain unauthorized access to the system.

Conceptual Example Code

The following pseudocode illustrates how an attacker might predict a session id:

import time
import hashlib
# Guess the epoch time
epoch_time = int(time.time())
# Guess the value from the rand function
rand_val = 12345  # This value is usually not secure
# Generate the session id
session_id = hashlib.md5(str(epoch_time) + str(rand_val)).hexdigest()
print("Predicted session id: " + session_id)

In the actual attack, the attacker would use this predicted session id to impersonate a valid user in the system.

Mitigation

To mitigate this vulnerability, it is recommended to apply the patch provided by the vendor. In the absence of a patch, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can be used as a temporary mitigation measure. However, these options do not address the root cause of the vulnerability and should be considered short-term solutions.