Analysis of CVE-2011-1852 Buffer Overflow in HP Intelligent Management Center TFTP Server

We recently published an article in Virus Bulletin which discussed the exploit technique which is possible due to the improper implementation of protocol specifications. This can lead to traditional exploitation vectors such as remote code execution and DoS attacks. In such cases, protocol specification documents are required to derive the condition for a IPS. I recently came across another vulnerability, which again is due to developers failing to follow the protocol specification document/RFC. The vulnerability is in the HP Intelligent Management Center TFTP Server (CVE-2011-1852). It is a case of buffer overflow in tftp.exe. Figure 1.0 show the capture when malicious bits are sent over the wire. Figure 1.0 showing the packet capture when exploit is send to trogger the vulnerable condition. The vulnerable condition gets triggered when processing overly long value to DATA and ERROR in TFTP packets. RFC 1350 provides details of TFTP protocol. As shown in figure 2.0, for TFTP protocol, the length of the data field should not exceed 512 bytes Figure 2.0 Showing the details of  the Protocol specification Hence in order to prevent the exploitation of the vulnerability, the detection device must ensure that the length of the data field is restricted to 512 bytes. At Alert Logic, our commitment is to provide the best protection against the emerging threats. We are monitoring the exploitation of the vulnerability. Acknowledgment I wanted to express my gratitude and thanks to Jacob for review and feedback. Abhishek