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#COBALT STRIKE BEACON DESKTOP VNC FULL#

An example of a loader using hardcoded IV and Key is shown in Figure 2:įigure 2: Payload hardcoded decryption details The 16-byte initialization vector (IV) and symmetric key are hardcoded into the DLL and can vary from sample to sample. The encrypted payload is read from disk and then AES-128 decrypted in CBC mode by the loader.

dat extension to it.įor example, if the malicious DLL is named LmiGuardianDLL.dll, the payload filename would be.

#COBALT STRIKE BEACON DESKTOP VNC FULL#

It does this by taking the full path it was loaded from and appending a.

Once loaded by the LogMeIn or Google binary, the malicious DLL will locate its corresponding encrypted payload.

Goopdate.dll side-loaded by a signed binary (GoogleUpdate.exe) from Google.

LMIGuardianDll.dll side-loaded by a signed binary (LmiGuardianSvc.exe) from LogMeIn.

We have observed two different variants of malicious loaders targeting popular applications which are likely to be found on most computers: This campaign uses a sideloading technique leveraging legitimate applications to load the first stage components of the malware. Attack Overviewįigure 1: Loader overview First Stage - Loader The main focus of this blog will be on PyXie RAT, but IOCs for other parts of the campaign will be listed in the Appendix.

Use of a modified RC4 algorithm to encrypt payloads with a unique key per infected host.

A custom compiled Python interpreter that uses scrambled opcodes to hinder analysis.

Use of Sharphound to collect active directory information from victims.

Use of a downloader with similarities to Shifu named "Cobalt Mode".

A Trojanized Tetris app to load and execute Cobalt Strike stagers from internal network shares.

Legitimate LogMeIn and Google binaries used to sideload payloads.

Key highlights of the PyXie campaign include:

Analysts have observed evidence of the threat actors attempting to deliver ransomware to the healthcare and education industries with PyXie.īlackBerry Cylance has conducted multiple incident response (IR) engagements in which PyXie was identified on hosts in the victim environment. It has been seen in conjunction with Cobalt Strike beacons as well as a downloader that has similarities to the Shifu banking Trojan. PyXie has been deployed in an ongoing campaign that targets a wide range of industries. PyXie has been observed in the wild since at least 2018 without much attention from the cybersecurity industry. BlackBerry Cylance researchers have recently discovered a previously unnamed Python RAT we’re calling PyXie.