CVE-2007-2446 in Samba
Summary
by MITRE
Multiple heap-based buffer overflows in the NDR parsing in smbd in Samba 3.0.0 through 3.0.25rc3 allow remote attackers to execute arbitrary code via crafted MS-RPC requests involving (1) DFSEnum (netdfs_io_dfs_EnumInfo_d), (2) RFNPCNEX (smb_io_notify_option_type_data), (3) LsarAddPrivilegesToAccount (lsa_io_privilege_set), (4) NetSetFileSecurity (sec_io_acl), or (5) LsarLookupSids/LsarLookupSids2 (lsa_io_trans_names).
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Analysis
by VulDB Data Team • 03/15/2025
The vulnerability described in CVE-2007-2446 represents a critical heap-based buffer overflow issue within the Named Data Representation (NDR) parsing functionality of Samba's smbd daemon. This flaw exists in Samba versions ranging from 3.0.0 through 3.0.25rc3 and specifically affects the parsing of Microsoft Remote Procedure Call (MS-RPC) requests. The vulnerability stems from inadequate input validation and bounds checking within the NDR parsing layer, which processes RPC data structures that Samba uses to communicate with Windows clients and servers. These buffer overflows occur when the system attempts to parse malformed or specially crafted RPC requests that exceed the allocated buffer space, creating opportunities for memory corruption and potential code execution.
The technical implementation of this vulnerability involves five distinct attack vectors that all share the common flaw of improper buffer handling during NDR parsing operations. The first vector targets DFSEnum (netdfs_io_dfs_EnumInfo_d) which handles DFS (Distributed File System) enumeration requests, the second involves RFNPCNEX (smb_io_notify_option_type_data) for notification option processing, the third focuses on LsarAddPrivilegesToAccount (lsa_io_privilege_set) for privilege management operations, the fourth targets NetSetFileSecurity (sec_io_acl) for security descriptor handling, and the fifth exploits LsarLookupSids/LsarLookupSids2 (lsa_io_trans_names) for SID translation functions. Each of these vectors demonstrates how the NDR parsing code fails to properly validate input sizes before copying data into fixed-length buffers, creating predictable memory corruption patterns that attackers can exploit to overwrite adjacent memory locations.
The operational impact of CVE-2007-2446 is severe and potentially catastrophic for affected systems. Remote attackers who successfully exploit any of these five vectors can achieve arbitrary code execution with the privileges of the smbd process, typically running as root or with elevated system privileges. This privilege escalation capability allows attackers to completely compromise the affected Samba server, potentially gaining access to all shared files and resources, establishing persistent backdoors, or using the compromised system as a launch point for further attacks within the network. The vulnerability's remote nature means that attackers do not require local access or authentication to exploit it, making it particularly dangerous in networked environments where Samba servers are exposed to untrusted networks. The heap-based nature of the overflow also makes exploitation more reliable and predictable compared to stack-based overflows, as heap corruption patterns are more consistent and easier to control.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1059.007 for command and script interpreter execution. The vulnerability represents a classic example of how protocol parsing flaws in network services can lead to remote code execution, highlighting the importance of robust input validation and memory safety practices. Organizations should immediately apply the available patches from Samba releases 3.0.25 and later, which contain fixes for the NDR parsing routines in all affected functions. Network segmentation and firewall rules should be implemented to restrict access to Samba services from untrusted networks, while monitoring should be enabled to detect suspicious RPC traffic patterns. Additionally, regular security assessments and vulnerability scanning should be conducted to identify any potential exploitation attempts or related vulnerabilities within the Samba ecosystem, ensuring comprehensive protection against similar issues that may arise from protocol parsing flaws in enterprise network services.