CVE-2016-8750 in Karaf
Summary
by MITRE
Apache Karaf prior to 4.0.8 used the LDAPLoginModule to authenticate users to a directory via LDAP. However, it did not encoding usernames properly and hence was vulnerable to LDAP injection attacks leading to a denial of service.
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Analysis
by VulDB Data Team • 02/08/2023
Apache Karaf versions prior to 4.0.8 contained a critical authentication vulnerability stemming from improper handling of user credentials during LDAP directory authentication processes. The vulnerability resided in the LDAPLoginModule implementation which failed to properly encode or sanitize user input before constructing LDAP search queries. This fundamental flaw created an avenue for malicious actors to inject specially crafted characters into the username field that would be interpreted as LDAP query operators or special characters within the directory search context. The lack of input sanitization allowed attackers to manipulate the underlying LDAP search operations through crafted usernames that could contain characters such as parentheses, asterisks, or other LDAP metacharacters.
The technical impact of this vulnerability extended beyond simple authentication bypasses, creating a potential denial of service condition that could severely impact system availability. When improperly encoded usernames were processed through the LDAP authentication module, the malformed search queries could cause the LDAP server to either reject the authentication request entirely or consume excessive computational resources during query processing. This behavior could lead to service disruption for legitimate users while simultaneously providing attackers with the ability to exhaust system resources through carefully constructed malicious inputs that would cause the LDAP server to process complex or malformed queries.
The operational implications of this vulnerability were significant for organizations relying on Apache Karaf for enterprise application management and deployment. Systems utilizing LDAP authentication for user access control became vulnerable to unauthorized access attempts and service disruption attacks that could compromise the integrity of the authentication infrastructure. The vulnerability particularly affected environments where Karaf was used as a container for enterprise applications requiring secure user authentication against centralized LDAP directories such as Active Directory or OpenLDAP servers. Organizations running affected versions faced potential unauthorized access to privileged management interfaces and could experience service degradation or complete denial of service during attack scenarios.
Security professionals should recognize this vulnerability as a classic example of improper input validation and sanitization within authentication modules, aligning with CWE-77 and CWE-78 categories related to command injection and improper neutralization of special elements. The flaw demonstrates how seemingly minor input handling issues can create significant security risks when operating in environments with privileged access controls. Organizations should immediately upgrade to Apache Karaf version 4.0.8 or later, which includes proper username encoding mechanisms for LDAP authentication. Additional mitigations should include implementing network-level access controls to limit exposure of Karaf management interfaces, monitoring authentication logs for suspicious patterns, and applying proper input validation at multiple layers of the authentication stack to prevent similar vulnerabilities from manifesting in other components.
The vulnerability also aligns with ATT&CK technique T1110.003 related to credential access through password guessing and credential dumping, as attackers could potentially exploit the LDAP injection to gain unauthorized access to directory services or escalate privileges within the authentication infrastructure. Organizations should consider implementing additional security controls including multi-factor authentication, privileged access management solutions, and comprehensive monitoring of authentication system behavior to detect and respond to potential exploitation attempts. The incident highlights the importance of proper input sanitization in authentication systems and serves as a reminder that even minor implementation flaws in security-critical components can have far-reaching consequences for system availability and data integrity.