OpenDJ, Denial-of-Service (DoS), CVE-2023-XXXX (Critical)

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How the CVE Works:

This vulnerability in OpenDJ arises due to improper handling of alias loops in the LDAP database. When an `ldapsearch` request is executed with alias dereferencing set to “always” on an alias entry that forms a loop, the server enters an infinite dereferencing cycle. This causes the server to become unresponsive to all LDAP requests, effectively resulting in a denial-of-service condition. The server does not crash or restart but remains stuck in the loop until manually restarted. The issue is exploitable by an unauthenticated attacker who can craft a single malicious `ldapsearch` request targeting the alias loop.

DailyCVE Form:

Platform: OpenDJ
Version: 9.2
Vulnerability: Denial-of-Service (DoS)
Severity: Critical
Date: 2023-XX-XX

(End of form)

What Undercode Say:

Exploitation:

1. Identify Alias Loops: Use the provided Python script (opendj_alias_dos.py) to detect alias loops in the LDAP database.
2. Craft Malicious Request: Execute an `ldapsearch` request with `DEREF_ALWAYS` on the identified alias loop.
3. Trigger DoS: The server will stop responding to all LDAP requests until restarted.

Protection:

1. Patch Update: Check for and apply the latest OpenDJ patches or updates addressing this vulnerability.
2. Alias Loop Detection: Regularly scan the LDAP database for alias loops using tools or scripts.
3. Limit Dereferencing: Configure OpenDJ to restrict or monitor alias dereferencing to prevent infinite loops.
4. Network Segmentation: Isolate the LDAP server to limit exposure to unauthenticated users.

Commands:

• Install `ldap3` library:

  pip install ldap3
  

• Run the exploit script:

  python opendj_alias_dos.py <IP> <PORT> <BASE_DN>
  

• Restart OpenDJ server:

  systemctl restart opendj
  

Code:

Example: Detect alias loops
aliases = find_aliases(connection, base_dn)
looping_alias_dn = detect_alias_loop(aliases)
if looping_alias_dn:
execute_dos_search(connection, looping_alias_dn)

URLs:

• OpenDJ Official Documentation: https://backstage.forgerock.com/docs/opendj/
• LDAP3 Python Library: https://ldap3.readthedocs.io/
• CVE Details: https://cve.mitre.org/

Analytics:

• Affected Systems: OpenDJ servers with alias entries in LDAP databases.
• Attack Vector: Unauthenticated network-based attack.
• Impact: High availability loss, requiring manual intervention.
• Mitigation Difficulty: Medium (requires configuration changes and monitoring).

References:

• OpenDJ GitHub Repository: https://github.com/OpenDJ/opendj
• LDAP Alias Dereferencing RFC: RFC 4511

References:

Reported By: https://github.com/advisories/GHSA-93qr-h8pr-4593
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