CVE-2019-3467 in Debian-edu-config
Summary
by MITRE
Debian-edu-config all versions < 2.11.10, a set of configuration files used for Debian Edu, configured too permissive ACLs for the Kerberos admin server, which allowed password changes for other Kerberos user principals.
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability identified as CVE-2019-3467 affects Debian-edu-config package versions prior to 2.11.10, representing a critical access control flaw within the Debian Edu distribution's Kerberos authentication infrastructure. This issue stems from improperly configured access control lists that govern the Kerberos administration server, creating a significant security weakness that undermines the integrity of the authentication system. The flaw specifically impacts the Kerberos user principal management functionality, where unauthorized entities can exploit the overly permissive permissions to modify passwords for other users within the Kerberos realm.
The technical implementation of this vulnerability involves the configuration of Kerberos Access Control Lists that fail to properly enforce the principle of least privilege. When Debian-edu-config installs or updates the Kerberos configuration, it establishes permissions that are excessively broad, allowing any authenticated user with access to the system to perform administrative operations on Kerberos principals. This misconfiguration directly violates security best practices and creates an attack surface that can be exploited by malicious actors to escalate privileges and gain unauthorized access to user accounts within the Kerberos infrastructure. The vulnerability operates at the application level, specifically targeting the Kerberos administration interface and its associated permission model.
From an operational perspective, this vulnerability presents a severe risk to organizations relying on Debian Edu for educational environments where Kerberos authentication is employed. The impact extends beyond simple privilege escalation, as attackers can potentially compromise multiple user accounts within the Kerberos realm, leading to unauthorized access to sensitive educational resources and data. The vulnerability affects the confidentiality, integrity, and availability of the authentication system, as unauthorized password modifications can result in account lockouts, unauthorized access to user resources, and potential data breaches. Organizations may experience cascading security failures if attackers leverage this vulnerability to gain access to additional systems that depend on Kerberos authentication.
The security implications of CVE-2019-3467 align with CWE-276, which addresses improper permissions and access control mechanisms. This vulnerability also maps to ATT&CK technique T1552.001, which covers "Unsecured Credentials" and represents how attackers can exploit weak access controls to obtain unauthorized access to user accounts. The flaw demonstrates a classic case of privilege escalation through misconfigured access controls, where the administrative functions should be restricted to authorized administrators but are instead accessible to any user with appropriate network access. Organizations should immediately implement the available patch for Debian-edu-config version 2.11.10 or later, which corrects the ACL configuration to properly restrict access to Kerberos administrative functions. Additionally, security teams should conduct comprehensive audits of Kerberos configurations across their infrastructure to identify and remediate similar misconfigurations, ensuring that access controls are properly enforced and that the principle of least privilege is maintained throughout the authentication system.