A Raccoon Stealer Weasels its Way Inside Telegram

A trash panda that steals user credentials has made its way into the Telegram chat app. The Raccoon Stealer stores and updates addresses, creating a new avenue for digital criminals to transmit malware.  

Is the Raccoon Stealer New?

This same credential stealer became popular several years ago. The updated version of the Raccoon Stealer makes it possible to implement alterations on the fly.

What Types of Addresses are Targeted?

The threat targets C2 addresses within the infrastructure of Telegram. C2 is short for command-and-control.  

Who is Behind the Attack?

The malware is likely the result of cyber thieves based in Russia. The credential stealer is also designed to perform additional harmful activity aside from stealing credentials. The threat even has the potential to steal cookies, usernames, passwords, browser form data, and email client login credentials. In some cases, the attack extends to crypto wallet files, messengers, arbitrary files, extensions, and plugins data.  

Vladimir Martyanov, a digital threat researcher with Avast Threat Labs, noted the Raccoon Stealer could download and execute arbitrary files from the C2 referenced above. Martyanov insists the Raccoon Stealer is dangerous as it updates on the fly and is regularly promoted within underground forums. The threat has a user-friendly design called MaaS, short for malware-as-a-service that sets the stage to make money with the theft of highly sensitive data.

How is the Attack Implemented?

The initial Raccoon Stealer attack centered on transmitting the Raccoon Stealer hosted within a Dropbox controlled by hackers as a component of business email. This attack compromises campaigns, zeroing in on specific financial institutions and other organizations.  

Researchers with Avast Threat Labs have also identified other ways that digital miscreants have distributed Raccoon Stealer. These researchers are sounding the alarm especially loudly as Raccoon Stealer is available on the dark web in a manner that allows users to take advantage of its diverse distribution techniques that are only limited by buyers’ creativity and aims in the context of digital criminal activity.

Let’s shift our focus to the nuances of how Raccoon Stealer spreads. The Stealer spreads using two loaders in GCleaner and Buer Loader. The Stealer is also implemented through fake patches and cheats implemented in cracked software such as video games. The games in question include popular titles ranging from NBA2K22 to Valorant and Fortnite.

How Does the Raccoon Stealer Bypass Protection?

The cybercriminals behind Raccoon Stealer have gone to great lengths to avoid detection. These miscreants sidestep identification with the discrete packaging of the credential stealer using malware packers and Themida. In some cases, the samples are packed more than four times within a single row inside an individual packer.

How is C2 Abused in Telegram?

The digital security specialists who have performed a deep dive into Raccoon Stealer’s communication with Telegram’s C2 identified four distinct important values for the transmission of information. These values are hardcoded into Raccoon Stealer samples.  

The TELEGRAM_Key value is a key that decrypts the C2 address obtained through the Telegram Gate. The BotID value is a hexadecimal string transmitted to the C2. Even the Telegram URL gates with channel names are used for hardcoding. Finally, the MAIN_Key value bolsters the functionality of the Raccoon Stealer samples.