Pierluigi Paganini
August 24, 2020
The Transparent Tribe APT group is carrying out an ongoing cyberespionage campaign aimed at military and diplomatic targets worldwide.
The group upgraded its Crimson RAT by adding a management console and implementing a USB worming capability that allows it to propagate from machines within an infected network.
The Operation Transparent Tribe was first spotted by Proofpoint Researchers in Feb 2016, in a series of cyber espionage operations against Indian diplomats and military personnel in some embassies in Saudi Arabia and Kazakhstan. At that time, the researchers tracked the sources IP in Pakistan, the attacks were part of a wider operation that relies on multi vector such as watering hole websites and phishing email campaigns delivering custom RATs dubbed Crimson and Peppy. These RATs are capable of exfiltrate information, take screenshot, and record webcam streams.
Transparent Tribe has been active since at least 2013, it targeted entities across 27 countries, most of them in Afghanistan, Germany, India, Iran and Pakistan.
The threat actor remained under the radar for a long period, in January Cybaze ZLab researchers gathered evidence on the return of Operation Transparent Tribe after 4 years of silence.
Crimson is a modular malware that supports multiple features, including:
Transparent Tribe has also implemented Crimson RAT a new USBWorm component used to steal files from removable drives, spreading across systems by infecting removable media, and downloading and executing a thin-client version of Crimson from a remote server.
“We found two different server versions, the one being a version that we named “A”, compiled in 2017, 2018 and 2019, and including a feature for installing the USBWorm component and executing commands on remote machines.” reads the analysis published by Kaspersky. “The version that we named “B” was compiled in 2018 and again at the end of 2019. The existence of two versions confirms that this software is still under development and the APT group is working to enhance it.”
By analyzing the .NET binary, the researchers were able to set up a working environment that allowed them to communicate with the detected samples.
Researchers discovered a .NET file that initially appeared as a variant of the Crimson RAT, but its analysis revealed that it was a server-side implant used to manage the client components.
The server includes a control panel, which displays the list of infected machines and shows basic information about them.
On top of the control panel, there is a toolbar that allows managing the server or one of the infected systems. At the bottom, there is an output console with displays a list of actions performed by the server in the background.
The interface includes a bot panel with 12 tabs, which allows managing a remote system and collect information. The tabs are associated with various features implemented by the Crimson components, such as exploring the remote file system; downloading, uploading and deleting files; keylogging; and monitoring the remote screen and checking what the user is doing on their system.
The analysis of the new USBWorm component in Crimson RAT revealed that it works as a downloader, infector and USB stealer.
“When started, it checks if its execution path is the one specified in the embedded configuration and if the system is already infected with a Crimson client component,” continues the analysis. “If these conditions are met, it will start to monitor removable media, and for each of these, the malware will try to infect the device and steal files of interest.”
The infection process for USBWorm begins with cataloging all directories of the victim device, then the malware creates a copy of itself in the drive root directory for each one, using the same directory name. The legitimate directories’ attribute is set to “hidden” while the actual directories are being replaced with a copy of the malware using the same directory name. USBWorm uses an icon that mimics a Windows directory to trick the user into launching the malware when trying to access one of the directories.
“This simple trick works very well on default Microsoft Windows installations, where file extensions are hidden and hidden files are not visible,” according to Kaspersky. “The victim will execute the worm every time he tries to access a directory. Moreover, the malware does not delete the real directories and executes ‘explorer.exe’ when started, providing the hidden directory path as argument. The command will open the Explorer window as expected by the user.”
The malware lists all files stored on the device and copies all the files with an extension of interest (i.e. .pdf, .doc, .docx, .xls, .xlsx, .ppt, .pptx, .pps, .ppsx and .txt.)
“Transparent Tribe continues to show high activity against multiple targets. In the last twelve months, we observed a broad campaign against military and diplomatic targets, using extensive infrastructure to support their operations and continuous improvements in their arsenal.” concludes Kaspersky. “The group continue to invest in their main RAT, Crimson, to perform intelligence activities and spy on sensitive targets. We do not expect any slowdown from this group in the near future and we will continue to monitor their activities.”
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(SecurityAffairs – hacking, transparent tribe)
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