Today, our honeypot intercepted a bagle sample to be detected as WORM_BAGLE.IN. As with the previous bagle variants, the new sample have several download URLs seen from its code and are already being monitored.
Yeah, same old bagle but something is unusual with the executable file. Using a tool called “hiew”, we can investigate the properties of the file. As seen in the following image the file is packed.
The tool said it has an “Entry Point” of 0x00000000; also another tool called PeiD flagged the file as a DLL (0 entry point).
However, the sample does execute whilst having a 0-entry point. After further investigation, the sample has an entry point found at the “MZ” header shown in the following image.
As we can see, there is a “push 00042a0a9” then followed by a “retn” instruction. The address, 00042a0a9, is the actual code entry point of the sample. So using OllyDbg, we can load the file and go to the entry point.
Oh, before I forget, here’s a snapshot of the email sample.
|File Size:||40,961 bytes|