CVE-2010-3972 in IIS
Summary
by MITRE
Heap-based buffer overflow in the TELNET_STREAM_CONTEXT::OnSendData function in ftpsvc.dll in Microsoft FTP Service 7.0 and 7.5 for Internet Information Services (IIS) 7.0, and IIS 7.5, allows remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via a crafted FTP command, aka "IIS FTP Service Heap Buffer Overrun Vulnerability." NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 01/20/2025
The CVE-2010-3972 vulnerability represents a critical heap-based buffer overflow flaw within the Microsoft FTP Service component that affects IIS 7.0 and 7.5 versions. This vulnerability specifically resides in the TELNET_STREAM_CONTEXT::OnSendData function located in the ftpsvc.dll module, which serves as the core implementation for FTP service operations within the Internet Information Services framework. The flaw arises from insufficient input validation and boundary checking when processing FTP commands, creating a scenario where maliciously crafted data can overwrite adjacent memory regions in the heap allocation space. This type of vulnerability falls under CWE-121, which specifically addresses heap-based buffer overflow conditions that occur when insufficient bounds checking is performed on heap-allocated memory regions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass full remote code execution capabilities. Attackers can exploit this weakness by sending specially crafted FTP commands that trigger the buffer overflow condition during the OnSendData processing phase. When the vulnerable function attempts to handle the malformed data, it writes beyond the allocated buffer boundaries, potentially overwriting critical memory structures including return addresses, function pointers, or other control data. This memory corruption can be leveraged to redirect execution flow to attacker-controlled code, effectively allowing remote attackers to execute arbitrary commands with the privileges of the FTP service account. The vulnerability's classification as a heap-based buffer overflow aligns with ATT&CK technique T1203, which covers the exploitation of memory corruption vulnerabilities to gain remote code execution.
The exploitation of this vulnerability requires minimal network interaction and can be performed from any remote location capable of establishing FTP connections to the affected IIS servers. The attack surface is particularly broad given that IIS 7.0 and 7.5 were widely deployed across enterprise environments, making this vulnerability attractive to threat actors seeking persistent access to network infrastructure. The daemon crash aspect of the vulnerability demonstrates the instability that occurs when memory corruption leads to process termination, while the remote code execution capability provides attackers with a more sophisticated attack vector for establishing backdoors, exfiltrating data, or conducting further network reconnaissance. Microsoft's security advisory for this vulnerability highlights the importance of immediate patch deployment and network segmentation strategies to prevent unauthorized access to FTP services. The vulnerability's presence in the core ftpsvc.dll component underscores the critical nature of maintaining up-to-date security patches for web server infrastructure components and implementing proper network access controls to limit exposure to such attacks.