CVE-2011-0530 in nbd
Summary
by MITRE
Buffer overflow in the mainloop function in nbd-server.c in the server in Network Block Device (nbd) before 2.9.20 might allow remote attackers to execute arbitrary code via a long request. NOTE: this issue exists because of a CVE-2005-3534 regression.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2011-0530 represents a critical buffer overflow condition within the Network Block Device (NBD) server implementation, specifically affecting versions prior to 2.9.20. This flaw resides in the mainloop function of the nbd-server.c file, which serves as the core processing loop for handling client requests. The NBD protocol enables block-level network access to remote storage devices, making this vulnerability particularly dangerous as it could potentially allow unauthorized remote code execution. The issue stems from a regression introduced by CVE-2005-3534, indicating that a previous fix for a different vulnerability inadvertently created this new security weakness.
The technical nature of this buffer overflow occurs when the server processes incoming requests without proper bounds checking on the length of data received from network clients. When a malicious attacker sends a request containing more data than the allocated buffer can accommodate, the excess data overflows into adjacent memory regions. This memory corruption can overwrite critical program variables, return addresses, or function pointers, ultimately allowing an attacker to manipulate the execution flow of the NBD server process. The vulnerability specifically targets the mainloop function which continuously processes client connections and request handling, making it a prime target for exploitation.
The operational impact of this vulnerability extends beyond simple remote code execution, as it can potentially allow attackers to gain full control over systems running vulnerable NBD servers. This is particularly concerning in enterprise environments where NBD servers might be used for storage virtualization, backup operations, or distributed storage solutions. The remote nature of the attack means that an attacker does not require physical access to the system or local network privileges to exploit this vulnerability. Successful exploitation could result in complete system compromise, data theft, or the establishment of persistent backdoors within the network infrastructure.
Mitigation strategies for CVE-2011-0530 primarily focus on immediate patching of affected NBD server implementations to version 2.9.20 or later, which contains the necessary fixes for the buffer overflow condition. Organizations should also implement network segmentation and access controls to limit exposure of NBD services to trusted networks only. Additionally, monitoring network traffic for unusually long requests and implementing intrusion detection systems can help identify potential exploitation attempts. From a compliance standpoint, this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a significant concern under ATT&CK technique T1059 for remote code execution. System administrators should also consider implementing network-based firewalls to restrict access to NBD ports and regularly audit their NBD server configurations to ensure they are running patched versions of the software.