CVE-2015-5330 in Samba
Summary
by MITRE
ldb before 1.1.24, as used in the AD LDAP server in Samba 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3, mishandles string lengths, which allows remote attackers to obtain sensitive information from daemon heap memory by sending crafted packets and then reading (1) an error message or (2) a database value.
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Analysis
by VulDB Data Team • 07/01/2022
The vulnerability identified as CVE-2015-5330 represents a critical heap-based information disclosure flaw within the Lightweight Directory Access Protocol implementation of Samba's Active Directory LDAP server. This vulnerability affects multiple versions of Samba 4.x series including 4.1.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3, with the underlying issue residing in the ldb library version prior to 1.1.24. The flaw manifests when the LDAP server processes malformed string length parameters in client requests, creating a scenario where attackers can exploit memory handling inconsistencies to extract sensitive data from the server's heap memory.
The technical exploitation mechanism involves sending specially crafted LDAP packets that manipulate string length parameters in ways that cause the ldb library to improperly handle memory allocation and data processing. When these malformed packets are received, the server's error handling routines or database value retrieval processes fail to properly validate string boundaries, leading to memory leaks that expose portions of the heap containing sensitive information. Attackers can then read either error messages or database values that contain confidential data such as user credentials, session tokens, or other privileged information stored in memory. This vulnerability operates at the protocol level within the LDAP implementation, making it particularly dangerous as it can be exploited through standard network connections without requiring authentication.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked heap memory can contain highly sensitive data including but not limited to authentication tokens, user session information, and potentially cryptographic keys. The vulnerability is classified under CWE-200 (Information Exposure) and aligns with ATT&CK techniques involving credential access and information gathering. Organizations running affected Samba versions face significant risk as attackers can systematically exploit this flaw to build comprehensive profiles of users and systems, potentially leading to privilege escalation or further attacks. The vulnerability's remote nature means that it can be exploited from anywhere on the network, making it particularly dangerous in enterprise environments where Active Directory services are critical for authentication and authorization.
Mitigation strategies for CVE-2015-5330 primarily involve immediate patching of affected Samba versions to the patched releases that contain corrected ldb library implementations. Organizations should prioritize updating their Samba installations to versions 4.1.22, 4.2.7, or 4.3.3 respectively, depending on their current version. Network segmentation and firewall rules should be implemented to restrict LDAP traffic to only trusted sources, while monitoring systems should be configured to detect unusual patterns in LDAP packet sizes or malformed requests. Additionally, implementing intrusion detection systems with signature-based detection for known exploit patterns can help identify attempts to leverage this vulnerability. The vulnerability's classification as a memory safety issue underscores the importance of regular security updates and maintaining current software versions to prevent exploitation of known memory corruption flaws that could lead to more severe security incidents.