CVE-2022-4254 in sssd
Summary
by MITRE • 02/01/2023
sssd: libsss_certmap fails to sanitise certificate data used in LDAP filters
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/01/2023
The vulnerability identified as CVE-2022-4254 affects the sssd (System Security Services Daemon) component, specifically within the libsss_certmap library responsible for certificate mapping operations. This flaw resides in how the system processes certificate data when constructing LDAP filters for authentication and authorization purposes. The issue manifests when certificate information is improperly sanitized before being incorporated into LDAP query structures, creating a potential injection vector that could be exploited by malicious actors. The sssd service plays a critical role in enterprise environments by providing unified identity management across multiple directory services including Active Directory, LDAP, and Kerberos. When certificate-based authentication is implemented through this daemon, the failure to properly sanitize certificate data creates a security weakness that directly impacts the integrity of the authentication pipeline.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the certificate mapping functionality. When certificates are processed for LDAP filtering operations, the system fails to adequately escape or validate special characters that have meaning within LDAP syntax. This allows an attacker who can influence certificate data to inject malicious LDAP filter components that could alter the intended query behavior. The flaw particularly affects scenarios where certificate attributes such as subject names, issuer information, or other certificate fields are directly incorporated into LDAP filter expressions without proper sanitization. According to CWE classification, this vulnerability maps to CWE-77 and CWE-94, representing improper neutralization of special elements used in a command and improper neutralization of special elements in a filter expression respectively. The vulnerability is categorized under the MITRE ATT&CK framework as part of the credential access and privilege escalation domains, specifically related to techniques involving authentication bypass and credential dumping through manipulation of authentication infrastructure components.
The operational impact of CVE-2022-4254 extends beyond simple data integrity concerns to potentially enable unauthorized access to systems relying on certificate-based authentication through sssd. An attacker exploiting this vulnerability could manipulate LDAP queries to bypass authentication controls, access unauthorized resources, or escalate privileges within the authenticated environment. The vulnerability is particularly concerning in enterprise environments where sssd is commonly deployed to manage identity federation across multiple domains and services. Organizations using certificate-based authentication mechanisms with sssd are at risk of having their certificate mapping operations compromised, potentially leading to full system compromise if the attacker can leverage the modified LDAP queries to gain elevated access. The attack surface is broad as the vulnerability affects any system using sssd with certificate mapping functionality, particularly those integrating with LDAP directories for authentication services.
Mitigation strategies for CVE-2022-4254 should focus on immediate patching of affected sssd versions, typically through updates from the operating system vendors or the sssd project maintainers. Organizations should also implement monitoring for unusual LDAP query patterns that might indicate exploitation attempts, particularly around certificate-related authentication flows. The implementation of proper input validation and sanitization within the certificate mapping components should be enforced through code reviews and security testing procedures. Additionally, network segmentation and access controls should be strengthened around systems running sssd to limit the potential impact of successful exploitation attempts. Security teams should also consider implementing certificate pinning and additional authentication layers to reduce the attack surface. The vulnerability highlights the importance of proper sanitization practices in authentication infrastructure components and aligns with security best practices outlined in NIST SP 800-160 and ISO/IEC 27001 standards for secure system design and implementation.