CVE-2015-5292 in System Security Services Daemon
Summary
by MITRE
Memory leak in the Privilege Attribute Certificate (PAC) responder plugin (sssd_pac_plugin.so) in System Security Services Daemon (SSSD) 1.10 before 1.13.1 allows remote authenticated users to cause a denial of service (memory consumption) via a large number of logins that trigger parsing of PAC blobs during Kerberos authentication.
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Analysis
by VulDB Data Team • 11/23/2024
The vulnerability identified as CVE-2015-5292 resides within the System Security Services Daemon sssd_pac_plugin.so module, specifically targeting the Privilege Attribute Certificate responder plugin. This memory leak affects SSSD versions 1.10 through 1.13.0, creating a persistent weakness that can be exploited by authenticated remote attackers. The flaw manifests during Kerberos authentication processes when PAC blobs are parsed, establishing a clear attack vector that leverages legitimate authentication sequences to achieve malicious objectives.
The technical implementation of this vulnerability stems from improper memory management within the PAC parsing logic of the SSSD daemon. When authenticated users perform numerous login operations that trigger PAC blob processing, the sssd_pac_plugin.so module fails to properly release allocated memory resources. This memory leak accumulates over time through repeated authentication attempts, gradually consuming system resources until the daemon becomes unresponsive or crashes entirely. The vulnerability operates at the protocol level during Kerberos authentication exchanges, specifically during the PAC validation phase where privilege attributes are processed.
The operational impact of CVE-2015-5292 represents a significant denial of service threat that can compromise system availability and service integrity. Attackers can systematically consume memory resources through legitimate authentication channels, making this vulnerability particularly dangerous in environments where continuous authentication is expected. The memory consumption grows progressively with each authentication attempt, potentially leading to complete daemon failure and service disruption for legitimate users. This type of attack can be executed without requiring privileged access beyond basic authentication credentials, making it an attractive vector for malicious actors seeking to disrupt service availability.
Security professionals should implement immediate mitigations including updating to SSSD version 1.13.1 or later, which contains the necessary patches to address the memory leak in the PAC responder plugin. Organizations should also consider implementing monitoring solutions to detect unusual authentication patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-401, which catalogs improper handling of memory allocation and deallocation issues, and maps to ATT&CK technique T1499.004 for network denial of service attacks. Additionally, system administrators should review and tighten authentication policies to limit the number of authentication attempts from single accounts and implement resource limits for authentication processes to prevent complete service exhaustion.