Implementing hidden storage makes forensic analysis more difficult since:
Malicious files are not stored in the file system (difficult to extract) Hidden storage cannot be decrypted without malware analysis Typical forensic tools do not work out of the box
To tackle the problem of retrieving the contents of the hidden storage areas one needs to perform malware analysis and reconstruct algorithms used to handle the data stored inside it. In the course of our research into complex threats we have developed a tool intended to recover the contents of hidden storage used by such complex threats as:
TDL3 and modifications TDL4 and modifications Olmasco Rovnix.A Rovnix.B Sirefef (ZeroAccess) Goblin (XPAJ) Flame (dump decrypted resource section)
The tool is very useful in incident response and threat analysis and monitoring. It is able to dump the malware’s hidden storage, as well as to dump any desired range of sectors of the hard drive. In the next figure a screenshot of the tool’s output is presented: