CVE-2007-6015 in Samba
Summary
by MITRE
Stack-based buffer overflow in the send_mailslot function in nmbd in Samba 3.0.0 through 3.0.27a, when the "domain logons" option is enabled, allows remote attackers to execute arbitrary code via a GETDC mailslot request composed of a long GETDC string following an offset username in a SAMLOGON logon request.
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Analysis
by VulDB Data Team • 01/25/2025
The vulnerability described in CVE-2007-6015 represents a critical stack-based buffer overflow affecting Samba's nmbd daemon, specifically within the send_mailslot function. This flaw exists in Samba versions ranging from 3.0.0 through 3.0.27a and becomes exploitable when the "domain logons" option is enabled, creating a significant security risk for systems relying on Samba for Windows domain integration. The vulnerability operates through a carefully crafted GETDC mailslot request that exploits the improper handling of input data within the mailslot processing mechanism.
The technical implementation of this buffer overflow occurs when the send_mailslot function processes a SAMLOGON logon request containing an offset username followed by an excessively long GETDC string. The function fails to properly validate the length of the incoming GETDC string, allowing an attacker to overflow the allocated stack buffer and overwrite adjacent memory locations. This overflow can be leveraged to overwrite the return address on the stack, enabling remote code execution with the privileges of the nmbd process. The vulnerability specifically targets the Windows domain logon functionality where Samba acts as a domain controller, making it particularly dangerous for enterprise environments relying on Samba for authentication services.
The operational impact of this vulnerability extends beyond simple remote code execution, as it can be exploited to gain unauthorized access to domain controller functionality and potentially escalate privileges throughout the network. Attackers can leverage this vulnerability to establish persistent access to domain environments, extract sensitive authentication information, or disrupt critical network services. The exploitation requires a remote attacker to send a specially crafted mailslot request to the nmbd daemon, making it a network-based attack that can be performed without authentication. The vulnerability affects systems where Samba is configured to handle domain logons, which includes many enterprise environments that rely on Samba for Windows domain integration.
The mitigation strategy for CVE-2007-6015 involves immediate patching of affected Samba versions to the latest available releases, specifically those beyond 3.0.27a where the buffer overflow has been addressed. System administrators should disable the "domain logons" option if it is not required for their environment, as this eliminates the attack vector entirely. Network segmentation and firewall rules should be implemented to restrict access to the nmbd service ports, particularly TCP 139 and 445, which are used for mailslot communication. Additionally, monitoring for unusual mailslot requests and implementing intrusion detection systems can help identify potential exploitation attempts. This vulnerability aligns with CWE-121 stack-based buffer overflow and maps to ATT&CK technique T1059 for remote code execution, making it a significant concern for enterprise security teams implementing Samba-based domain solutions. Organizations should also conduct comprehensive vulnerability assessments to identify any other potentially affected systems running vulnerable Samba versions and ensure proper configuration management to prevent unauthorized enabling of domain logon functionality.