CVE-2023-44038

Executive Summary

CVE-2023-44038 is an LDAP injection vulnerability in VeridiumID, an identity and access management platform, affecting versions prior to 3.5.0. An unauthenticated attacker can exploit the identity provider page to inject arbitrary LDAP filters, enabling the discovery of registered usernames and other directory information. This information disclosure can serve as a stepping stone for targeted attacks, such as password spraying or credential stuffing. The vulnerability has a public proof-of-concept (PoC) and no known patch details beyond upgrading to the fixed version.

Supply Chain & Package Security

VeridiumID is a proprietary enterprise software product, not distributed via public package registries (NPM, PyPI, Go, Ruby). Therefore, supply chain security considerations are limited to the vendor's internal build and distribution processes. Organizations should verify the integrity of the downloaded installer via checksums provided by Veridiumid.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0 in the NVD data, which is likely a placeholder or error. Based on the vulnerability characteristics, a reasonable CVSS v3.1 vector would be:

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Base Score: 5.3 (Medium)
Vector String: AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Breakdown:

• Attack Vector (AV): Network – exploitable remotely.
• Attack Complexity (AC): Low – no special conditions required.
• Privileges Required (PR): None – unauthenticated.
• User Interaction (UI): None – no user action needed.
• Scope (S): Unchanged – vulnerability does not affect other components.
• Confidentiality (C): Low – limited information disclosure (usernames).
• Integrity (I): None – no data modification.
• Availability (A): None – no denial of service.

Threat Level: Medium. The vulnerability allows information gathering but not direct system compromise. However, it can be chained with other attacks.

Deep Dive & Mechanics

The vulnerability resides in the identity provider (IdP) page of VeridiumID. The IdP page likely accepts user input (e.g., username or email) to look up or validate users against an LDAP directory. The application fails to properly sanitize or escape user-supplied input before constructing an LDAP query.

LDAP Injection Mechanics:

1. The application builds an LDAP filter string by concatenating user input directly.
2. An attacker can inject LDAP metacharacters such as *, (, ), |, &, !, and = to alter the filter logic.
3. For example, injecting * into a username field may cause the filter to match all entries, revealing valid usernames through response differences (e.g., error messages, timing, or successful authentication attempts).

Example Attack:

• Normal request: username=john.doe → filter: (uid=john.doe)
• Malicious request: username=* → filter: (uid=*) → returns all users.
• More advanced: username=admin)(|(uid=* → filter: (uid=admin)(|(uid=*) → may cause an error or return multiple entries.

The attacker can enumerate valid usernames by observing application responses (e.g., "User not found" vs. "Invalid password").

Vulnerable vs. Patched Code

Since VeridiumID is proprietary, exact code snippets are not available. However, the vulnerable pattern is:

Vulnerable (pseudo-code):

def search_user(username):
    filter = f"(uid={username})"
    results = ldap_search(base_dn, filter)
    return results

Patched (pseudo-code):

def search_user(username):
    safe_username = ldap_escape(username)  # Escape LDAP special characters
    filter = f"(uid={safe_username})"
    results = ldap_search(base_dn, filter)
    return results

The patch involves proper input validation and escaping of LDAP metacharacters using a library function like ldap_escape() or filter_escape().

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable VeridiumID instance (version < 3.5.0) in a controlled environment.
2. Configure an LDAP backend (e.g., OpenLDAP) with test user accounts.
3. Access the identity provider page (e.g., https://target/idp).

Exploitation Steps:

1. Intercept the login/validation request using Burp Suite or similar.
2. Modify the username parameter to inject LDAP wildcards:
   • username=* – may return all users.
   • username=admin)(uid=* – attempts to bypass filters.
3. Observe responses: a successful enumeration may show different error messages or redirects.
4. Use a tool like ldapsearch or custom script to automate enumeration.

Example curl command:

curl -X POST "https://target/idp/validate" \
  -d "username=*&password=test"

Blue Team

Detection:

• Monitor for unusual LDAP query patterns in application logs.
• Look for requests containing LDAP metacharacters (*, (, ), |, &, !, =) in username fields.
• Alert on multiple failed authentication attempts with varying usernames.

Hunting:

• Search web server logs for requests to /idp or similar endpoints with suspicious parameters.
• Correlate with LDAP server logs for unexpected queries (e.g., (uid=*)).

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /idp or /idp/validate with username parameters containing LDAP metacharacters.
  • Unusual LDAP queries in directory server logs (e.g., (uid=*), (cn=*)).
• Log IOCs:
  • Application logs showing "User not found" for multiple usernames in rapid succession.
  • LDAP server logs with high query rates from a single source IP.
• File IOCs:
  • None specific to this CVE.

Detection Engineering

YARA Rule

rule CVE_2023_44038_LDAP_Injection {
    meta:
        description = "Detects LDAP injection attempts targeting VeridiumID"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-44038"
    strings:
        $ldap_meta1 = "*"
        $ldap_meta2 = "("
        $ldap_meta3 = ")"
        $ldap_meta4 = "|"
        $ldap_meta5 = "&"
        $ldap_meta6 = "!"
        $ldap_meta7 = "="
        $url_path = "/idp"
    condition:
        any of ($ldap_meta*) and $url_path
}

Sigma Rule

title: LDAP Injection Attempt Against VeridiumID
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects LDAP injection attempts in HTTP requests to VeridiumID identity provider
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-stem:
            - "/idp"
            - "/idp/validate"
        cs-uri-query|contains:
            - "*"
            - "("
            - ")"
            - "|"
            - "&"
            - "!"
            - "="
    condition: selection
falsepositives:
    - Legitimate use of special characters in usernames (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-44038 LDAP Injection Attempt"; flow:to_server; content:"/idp"; http_uri; content:"*"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade VeridiumID to version 3.5.0 or later.
2. If immediate upgrade is not possible, implement a Web Application Firewall (WAF) rule to block requests containing LDAP metacharacters in username fields.
3. Restrict network access to the VeridiumID interface to trusted IPs only.

Long-term Mitigations:

• Conduct a security audit of all input handling in the application.
• Implement input validation and output encoding for all user-supplied data.
• Use parameterized LDAP queries or ORM libraries that handle escaping automatically.
• Enable detailed logging and monitoring for LDAP queries.

Workaround:

• Disable the identity provider page if not required, or implement CAPTCHA to slow down automated enumeration.

Valters IT