I received an Invoice.MHT file attached to an email: The URL points to an HTA file: We can see a PowerShell command with BASE64. This can be dumped with base64dump: As expected, it is UNICODE: We can try to decode this as UTF-16: And we get an error, because of some unprintable characters. These can be seen here: A trick to deal with such characters, is to decode as UTF-16 and encode as ASCII, but ignore errors, like this: The downloaded executable is not detected by a lot of anti-virus programs. Didier Stevens |
DidierStevens 650 Posts ISC Handler Feb 3rd 2018 |
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Feb 3rd 2018 4 years ago |
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