Info Stealer Targeting Browsers and Crypto Wallets
The popularity of Cryptocurrency has increased exponentially over the recent years as dealing with crypto has become relatively hassle-free and more accessible. The financial returns of crypto investments have attracted many investors to invest in crypto markets.
As the demand for crypto investment has increased over the years, we can also see a corresponding rise in the number of crypto wallets. Some popular crypto wallets such as Binance, Atomic, Exodus, Coinbase, Metamask, and Trust are the most commonly used platforms to manage and transact Cryptocurrency.
Despite gaining popularity worldwide, Cryptocurrency also has its downsides. It opens the door for various malicious activities like phishing, scams, hacking, delivering malware, etc.
Cyble Research Labs has constantly been tracking malicious activities targeting Cryptocurrency wallets. During a routine threat-hunting exercise, we came across a Twitter post where a researcher mentioned a fake Atomic wallet site distributing Mars Stealer.
The phishing site “hxxp://atomic-wallet[.]net” uses the icon and name of the Atomic wallet. Additionally, the Threat Actor is trying to copy the UI of a genuine website to trick the user, as shown in the below image.
Upon investigating the phishing site, we observed that the TA has invested time in developing a well-designed phishing site to trick victims into downloading the malware.
The phishing site appears to be genuine as the TA provided some attractive content such as Trusted Reviews, Cashback, FAQ, Partners, Contact Us page, Support, and Update History.
When the user interacts with the “Download” button, the phishing site redirects to the download options page, where the user can download Atomic wallet for Windows, iOS, and Android, as shown in the below image.
The App Store button is inactive while, the Google Play button redirects the user to the genuine Atomic Wallet Play Store link.
When the user clicks on the “Download for Windows” button, it connects to shortened URL “hxxps://bit[.]ly/3PRDyH8” and downloads a Zip file named “Atomic Wallet.zip“.
After a detailed investigation, the downloaded file was identified as a Mars Stealer sample. Mars Stealer was discovered in June 2021 and was available for sale on a few underground cybercrime forums. Mars stealer primarily targets browser extensions, crypto extensions and wallets, and 2FA plugins.
The downloaded Zip file contains the “AtomicWallet-Setup.bat” file containing malicious code, as shown in the below image.
Upon execution, the .bat file invokes the Powershell command, enabling the administrative elevation for its execution.
The .bat file then copies powershell.exe into the current directory, renames it as AtomicWallet_Setup.bat.exe, and then hides it using the attrib command.
Then, the .bat file executes PowerShell content using AtomicWallet_Setup.bat.exe, which further decodes the base64-encoded content and decrypts it using an AES algorithm that stores a Gzip Compressed stream in the memory.
The below figure shows the code used by the malware to perform AES decryption and GZip Decompression.
Finally, the malware decompresses the GZip content and loads the final PowerShell code that downloads Mars Stealer from the Discord server to the victim’s %LOCALAPPDATA% location.
The below figure shows the infection chain of Mars Stealer. After downloading Mars stealer, the .bat file deletes the “AtomicWallet_Setup.bat.exe” from the victim’s machine.
After successful installation, Mars Stealer steals sensitive information from the victim’s device and exfiltrates the stolen data to the C&C server.
According to our research, the TAs behind Mars stealer are adopting sophisticated phishing attacks to distribute Mars Stealer and gather user credentials, system information, and other sensitive data.
The criminals may use compromised credentials to carry out attacks to stay under the radar and avoid tripping any security monitoring rules, thus alerting any victims to the attempted compromise.
- Avoid downloading pirated software from unverified sites.
- Use strong passwords and enforce multi-factor authentication wherever possible.
- Keep updating your passwords after certain intervals.
- Use a reputed anti-virus and internet security software package on your connected devices, including PC, laptop, and mobile.
- Refrain from opening untrusted links and email attachments without first verifying their authenticity.
- Block URLs that could be used to spread the malware, e.g., Torrent/Warez.
- Monitor the beacon on the network level to block data exfiltration by malware or TAs.
- Enable Data Loss Prevention (DLP) Solutions on employees’ systems.
MITRE ATT&CK® Techniques
|Tactic||Technique ID||Technique Name|
|Defense Evasion||T1564||Hidden Files and Directory|
|Defense Evasion||T1027||Obfuscated Files or Information|
|Credential Access||T1555 |
|Credentials from Password Stores |
Steal Web Session Cookies
Steal Application Access Token
|Discovery||T1082||System Information Discovery|
|Exfiltration||T1041||Exfiltration Over C&C Channel|
Indicators Of Compromise (IOCs)
|33d0d9fe89f0dba2b89347a0e2e6deb22542476d98676187f8c1eb529cb3997f||SHA256||Hash of the analyzed bat file|
|dfdbb09661ee90ad4e88e7b0510653c93485a4b2||SHA1||Hash of the analyzed bat file|
|3004914cdfa67357410e6f0c9a091655||MD5||Hash of the analyzed bat file|
|10afe233525aaf99064e4e444f11a8fc01f8b9f508e4f123fd76b314a6d360f9||SHA256||Hash of the analyzed Mars Stealer exe file|
|0f6e3442c67d6688fae5f51b4f60b78cd05f30df||SHA1||Hash of the analyzed Mars Stealer exe file|
|10f0d3a64949a6e15a9c389059a8f379||MD5||Hash of the analyzed Mars Stealer exe file|
|hxxps://atomic-wallet[.]net||URL||Malware distribution site/C&C server|