CVE-2015-1827 in FreeIPA
Summary
by MITRE
The get_user_grouplist function in the extdom plug-in in FreeIPA before 4.1.4 does not properly reallocate when processing user accounts, which allows remote attackers to cause a denial of service (crash) via a group list request for a user that belongs to a large number of groups.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/02/2022
The vulnerability identified as CVE-2015-1827 resides within the extdom plug-in of FreeIPA software version 4.1.3 and earlier, representing a critical denial of service flaw that stems from improper memory management during group list processing. This issue manifests when the get_user_grouplist function fails to correctly reallocate memory buffers while handling user accounts that belong to an excessive number of groups, creating a scenario where remote attackers can exploit this weakness to crash the system. The vulnerability operates at the core level of user account processing within the identity management infrastructure, making it particularly dangerous as it directly impacts the availability of the authentication and authorization services that FreeIPA provides to organizations.
The technical implementation of this flaw involves the memory allocation mechanism within the extdom plug-in's get_user_grouplist function, which does not adequately handle scenarios where user accounts are members of numerous groups. When a group list request is made for such users, the function attempts to process the extensive group membership data but fails to properly reallocate memory resources, leading to buffer overflow conditions or memory corruption that ultimately results in application crashes. This behavior aligns with CWE-122, which describes improper reallocation vulnerabilities, and represents a classic example of how insufficient bounds checking and memory management can create exploitable conditions. The vulnerability specifically targets the memory management practices within the extdom plug-in, which is responsible for extending domain functionality beyond basic identity management.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on FreeIPA for their identity management needs, as it can be exploited remotely without requiring authentication credentials. Attackers can simply submit a group list request for a user account known to belong to many groups, triggering the memory reallocation failure that causes the FreeIPA service to crash and become unavailable. This denial of service condition can persist until the service is manually restarted, potentially disrupting authentication services for all users within the domain and creating operational downtime that can span from minutes to hours depending on the recovery process. The impact extends beyond simple service disruption as it can affect the entire identity management infrastructure, potentially causing cascading failures in systems that depend on FreeIPA for user authentication and authorization.
Organizations should implement immediate mitigations including upgrading to FreeIPA version 4.1.4 or later, which contains the necessary patches to address the memory reallocation issue in the extdom plug-in. Additionally, network-level firewalls and access controls should be configured to limit access to the FreeIPA services to trusted networks only, reducing the attack surface for remote exploitation attempts. System administrators should also implement monitoring solutions to detect unusual patterns in group list requests that might indicate exploitation attempts, and establish automated alerting mechanisms to notify security teams of potential service disruptions. The remediation process should include comprehensive testing of the patched version in non-production environments before deployment to ensure that the fix does not introduce compatibility issues with existing configurations or integrations. This vulnerability demonstrates the critical importance of proper memory management in security-critical applications and serves as a reminder of how seemingly minor implementation flaws can result in significant availability impacts.