Peeking at Pkybot
For the past few months ASERT has been keeping an eye on a relatively new banking malware (“banker”) known as “Pkybot”. It is also being classified as a variant of “Bublik”, but the former is much more descriptive of the malware.
This post will take a peek at some of the bits and pieces of Pkybot and the campaign using it. The visibility provided can help organizations better understand, detect, and protect against this current threat.
Sample
One of the recent samples analyzed by ASERT has the following hashes:
MD5: 9028d9b64a226b750129b41fbc43ed5e
SHA256: 38eb7625caf209ca2eff3fa46b8528827b7289f1
At the time of this writing it has a VirusTotal detection ratio of 16/57 with just about all the detections being generic in nature. One positive for reverse engineers though is that this sample comes unpacked.
Pkybot
While there’s been some research into the malware already [1] [2], a review and fleshing out never hurts.
Encrypted Bits
Pkybot contains a number of interesting items that are encrypted with the XTEA encryption algorithm. The key used is generated at runtime from a hardcoded seed value (DWORD):
It can also be generated using this Python code snippet. Along with the generated XTEA key, this IDA Continue reading