Rewterz Threat Alert – NjRAT Leverages PasteBin for Second Stage Payload

Severity

High

Analysis Summary

NjRat is a Remote Access Trojan, which is found leveraging Pastebin to deliver second-stage payload after initial infection. There are multiple versions of the secondary payload used, ranging from base64 encoded version, hexadecimals, JSON data format, compressed blobs and also plain text data with malicious URLs embedded within. This is done in order to evade detection by security products and increase the possibility of operating unnoticed. njRat is developed in .NET framework and is able to hijack the functions of a compromised machine remotely, including taking screenshots, exfiltrating data, keylogging, and killing processes such as antivirus programs, while also connecting the machine to a botnet. RAT was also found abusing Windows API functions such as Windows API calls such as GetKeyboardState(), GetAsynckeyState(), MapVirtualKey() for keylogging and data theft. It was also discovered downloading web scraping tools such as “proxy scrapper” in order to extract large amount of data via proxies.

Impact

• Detection Evasion
• Unauthorized Remote Access
• Data Exfiltration
• Credential Theft
• Process Termination
• Device Takeover

Indicators of Compromise

Domain Name

• textfiles[.]us

MD5

• b76e91a7cc9913fc7b7740e9507507eb
• d0f4935873c920bbe948c2bd5db6ba23
• 1421c723c706afc55cd4a8493d2e109e
• 62a9f4e3d941646a113731b80d1e1ea7
• d4229f31b65eedc2c68a86e9453b2c2d
• 0775c4c17171a558d9bac84d6891f73c
• 66e346b6bc7da2bab814d3c5ab2beac7
• c2d6fd768ca41f8b36b360c97937900e
• b40c9009915839748dee0581cfc00f9f

SHA-256

• db8ca46451a6c32e3b7901b50837500768bb913cafb5e12e2111f8b264672219
• bdc33dbdfd92207ad88b6feb3066bb662a6ca5cf02710870cae38320bb3a35bf
• bd2387161cc077bfca0e0aae5d63820d1791f528feef65de575999454762d617
• 9ba0126bd6d0c4b41f5740d3099e1b99fed45b003b78c500430574d57ad1ad39
• 9982c4d431425569a69a022a7a7185e8c47783a792256f4c5420f9e023dee12a
• 97b943a45b4716fcea4c73dce4cefe6492a6a51e83503347adcd6c6e02261b84
• 97227c346830b4df87c92fce616bdec2d6dcbc3e6de3f1c88734fe82e2459b88
• 96640d0c05dd83bb10bd7224004056e5527f6fad4429beaf4afa7bad9001efb7
• 03c7015046ef4e39a209384f2632812fa561bfacffc8b195542930e91fa6dceb

SHA1

• b7837d2c8ec63d68b1df33f5f13f39182db129fc
• 76c9e73c1c371a6c7eaff271c81c48653c9bbe95
• 80a66c9a9e49c6fcfabfbc2fac4899e4723906ca
• fee24c409577f4d341d35799b965753a3cf71d06
• c62fdd5598029404c8171afdd85cdb09dccc2150
• 9f75578dabaf4a7c10798ff882496de52882ea27
• b1dc3b89cc6493e0c07b8fa898ceea863b067a34
• df0b9f5e5e9eb70b2e7fcaae110a3dfb1726b45e
• 9f945a6aed00a54d7f2c52ead58e200635ff5567

URL

• http[:]//textfiles[.]us/driverupdate0[.]exe

Remediation

• Block the threat indicators at their respective controls.
• Do not click on untrusted URLs.