This is a screenshot of the files before encryption by Dharma:Īfter encryption, each has a different file size and signature: Because the files are all the same type, size, and have the same content, they all share the same SHA1 signature – 9ea0e7343beea0d319bc03e27feb6029dde0bd96. We named the three files as ‘autorun.inf’, ‘boot.sdi’ and ‘bootsect.exe’ and moved each to a different location. The cybersecurity team tested the encryption complexity of Dharma 2.0 by creating three identical, 5 line text files with the following content: It creates a copy of itself in, , and adds the extension ].wiki’ to the end of all encrypted files:Ĭ:\users\administrator\appdata\local\temp\about.dbĬ:\users\administrator\appdata\local\temp\about.db-journalĬ:\users\administrator\appdata\roaming\microsoft\windows\start menu\programs\startup\Wadhrama 2.0.exeĬ:\programdata\microsoft\windows\start menu\programs\startup\Wadhrama ].wikiĬ:\msocache\all ].wiki Static analysis of Dharma 2.0 Wadhrama 2.0.exe creates two sql files, ‘about.db’ and ‘about.db-journal’ in. ‘Info.hta’ is the file which contains the ransom note: It does this by using ‘mshta.exe’ to open ‘Info.hta’ as an auto-run with the command Many businesses have such backups in place, but an alarming number do not.Īfter encrypting all files on the computer, the attacker now needs a way to communicate their instructions to the victim. With the shadow copies gone, users cannot restore their files unless they have an external, 3rd party backup in place.
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The command ‘vssadmin delete shadows /all /quiet’ is commonly used in ransomware to delete existing Windows restore points, robbing the user of a backup of their files: The malware uses the DOS device mode utility to gather some information about the victim’s keyboard and deletes any shadow copies of their files. The execution tree of the malware is shown in the screenshot below, with ‘Wadhrama 2.0.exe’ at the head of the list: Process Execution Hierarchy of Dharma 2.0 Let’s take a close look at the details of Dharma 2.0, with the help of the Comodo Cyber Security team. This version contains the core encrypt-then-ransom functionality of previous versions, but also contains an additional backdoor which grants remote admin capabilities. In February 2020, the Comodo Cyber Security team discovered the latest evolution of this malware, Dharma 2.0.
Of course, the attachment isn’t an antivirus program, it’s Dharma 2.0, which then proceeds to encrypt the user’s files and demand a ransom to unlock them.
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It contains a warning about malware on their machine and instructs them to install the attached antivirus file to remove the threat. The victim receives an email that looks as though it comes from their real-life antivirus provider. The latter method is a classic email attack. From there, the attacker has complete control over the target machine and runs the Dharma ransomware manually on the user’s files. Once a target is found, the attacker tries to login to the connection by automatically trying different passwords from a huge library of known passwords, until one of them works. The first method involves the attacker scanning port 3389 for connections that use the RDP protocol. The Dharma trojan is delivered by brute-forcing weak passwords on RDP connections, or by getting the victim to open a malicious email attachment. As with virtually all strains of ransomware, the files are completely unrecoverable without the decryption key, and the victim must pay the ransom to get the key. It targeted Windows systems and encrypts victim’s files with strong AES-256 and RSA-1024 algorithms, before demanding a ransom in Bitcoins. The malware first appeared in 2016 under the name CrySIS. Today we’d like to tell you about a newer version of the ransomware called Dharma version 2.0. The Comodo Cyber Security team constantly researches the latest ransomware to help better protect our users and to share our findings with the wider netsec and antivirus communities. Comodo Cyber Security team reveals the inner-workings of the latest strain of this persistent threat
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