Loncom packer: from backdoors to Cobalt Strike


The previous story described an unusual way of distributing malware under disguise of an update for an expired security certificate. After the story went out, we conducted a detailed analysis of the samples we had obtained, with some interesting findings. All of the malware we examined from the campaign was packed with the same packer, which we named Trojan-Dropper.NSIS.Loncom.

The malware uses legitimate NSIS software for packing and loading shellcode, and Microsoft Crypto API for decrypting the final payload. Just as the earlier find, this one was not without its surprises, as one of the packaged samples contained software used by APT groups.

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Source: Kaspersky