CVE-2015-2704 in realmd
Summary
by MITRE
realmd allows remote attackers to inject arbitrary configurations in to sssd.conf and smb.conf via a newline character in an LDAP response.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 11/27/2024
The vulnerability identified as CVE-2015-2704 resides within the realmd service which is responsible for managing domain membership and configuration for Linux systems connecting to Active Directory environments. This flaw represents a critical configuration injection vulnerability that allows remote attackers to manipulate the sssd.conf and smb.conf configuration files through carefully crafted LDAP responses. The vulnerability specifically exploits the handling of newline characters within LDAP response data, enabling attackers to inject malicious configuration directives that get processed by the sssd service during domain joining operations.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the realmd component when processing LDAP attributes that contain user-supplied data. When realmd processes LDAP responses containing newline characters in configuration values, it fails to properly escape or filter these characters before writing them to the sssd.conf and smb.conf files. This allows an attacker positioned to manipulate LDAP responses to inject additional configuration directives, potentially including commands or settings that could compromise system security. The vulnerability specifically affects systems using the sssd service for authentication and the smb.conf file for SMB/CIFS configuration management, creating a pathway for attackers to modify critical system parameters.
The operational impact of this vulnerability is significant as it provides remote attackers with the capability to modify essential system configuration files without requiring local access or authentication. An attacker could potentially inject malicious configuration parameters that redirect authentication requests to malicious servers, disable security features, or establish backdoor access mechanisms within the domain environment. The compromise of sssd.conf and smb.conf files could lead to credential theft, privilege escalation, or complete domain compromise depending on the injected configuration values. This vulnerability particularly affects enterprise environments where realmd is used for automated domain joining and where LDAP servers might be accessible to untrusted parties.
Mitigation strategies for CVE-2015-2704 should focus on immediate patching of affected realmd versions and implementation of LDAP response validation measures. Organizations should ensure all systems running realmd are updated to versions that properly sanitize LDAP response data before configuration file generation. Network segmentation and LDAP server access controls should be implemented to limit exposure to untrusted LDAP sources. The vulnerability aligns with CWE-174 which addresses insufficient input sanitization in configuration file generation processes, and maps to ATT&CK technique T1543.003 for creating or modifying system level configuration files. Additional defensive measures include monitoring for unusual configuration file modifications and implementing strict access controls for LDAP servers that provide domain join services.