CVE-2014-9217 in Graylog2
Summary
by MITRE
Graylog2 before 0.92 allows remote attackers to bypass LDAP authentication via crafted wildcards.
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Analysis
by VulDB Data Team • 04/07/2022
The vulnerability identified as CVE-2014-9217 affects Graylog2 versions prior to 0.92 and represents a critical authentication bypass flaw within the LDAP integration component. This issue stems from insufficient input validation and sanitization mechanisms that process LDAP search filters containing crafted wildcard characters. The vulnerability specifically targets the authentication flow where Graylog2 interacts with LDAP servers to verify user credentials, creating a pathway for malicious actors to circumvent the intended security controls. Attackers can exploit this weakness by submitting specially crafted LDAP search queries that contain wildcard characters, which are then improperly handled by the Graylog2 authentication module, potentially allowing unauthorized access to the system.
The technical implementation of this vulnerability resides in the LDAP filter construction and processing logic within Graylog2's authentication subsystem. When users attempt to authenticate through LDAP, the system constructs search filters to query the directory service for matching user entries. The flaw occurs when the application fails to properly escape or sanitize special LDAP wildcard characters such as asterisks, which can be used to manipulate the search filter syntax. This improper handling allows attackers to craft authentication requests that bypass the normal validation procedures, effectively creating a backdoor into the system's authentication mechanism. The vulnerability operates at the intersection of input validation and access control, where the application's trust in user-provided LDAP search parameters is exploited to gain unauthorized access.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it can enable attackers to escalate privileges and potentially compromise the entire Graylog2 deployment. Since Graylog2 serves as a centralized log management and monitoring solution, unauthorized access could provide attackers with visibility into sensitive system logs, network traffic analysis, and security event data. The authentication bypass allows threat actors to impersonate legitimate users or gain administrative access to the Graylog2 interface, potentially leading to data exfiltration, log manipulation, or disruption of monitoring capabilities. This vulnerability particularly affects organizations that rely heavily on LDAP-based authentication and centralized log management systems, where the compromise of authentication mechanisms can have cascading effects throughout the security infrastructure.
Organizations should implement immediate mitigations including upgrading to Graylog2 version 0.92 or later, which contains the necessary patches to address the LDAP wildcard handling issue. The fix typically involves implementing proper input sanitization and escaping mechanisms for LDAP search filters, ensuring that wildcard characters are appropriately handled and do not alter the intended search behavior. Network segmentation and access controls should be strengthened to limit exposure, while monitoring should be enhanced to detect unusual authentication patterns that might indicate exploitation attempts. Security teams should also conduct thorough audits of their LDAP configurations and authentication flows to identify any other potential vulnerabilities in their directory service integrations. This vulnerability aligns with CWE-1271, which addresses improper handling of special characters in search filters, and represents a significant concern for organizations following ATT&CK framework tactics related to credential access and privilege escalation.