qkG Filecoder is the First Ransomware that capable of self Self-Replicating capabilities from one file to another, and unlike other ransomware families, its uses malicious macro code to downloading the ransomware.
The malicious macro code is one of the techniques that is used by a .lukitus variant of Locky ransomware which is capable of auto close VBA Script.
qkG capable of encrypting the document content but it won’t damage the file structure, and it will not change the file name as well.
It affects only an ActiveDocument which means that will just Encrypt the opened documents and no ransom notes will be added to the system.
According to macro malware body, The qkG was named by its developer, and these samples were added by to VirusTotal from Vietnam.
How does qkG Filecoder infection chain work
Once Victims enables the macros, the normal.dot template will be modified and get infected with malicious macros.
Whenever victims will open the word, Malicious normal.dot template will be loaded and executed into the memory.
qKG will not perform any task whenever the user opens the uninfected document. Later, it will encrypt the file content once a user tries to close the particular opened document.
Next stage it will display the message with an email and Bitcoin address, along with the encrypted content.
qkG Filecoder uses the Document_Open() autostart macro to repeat the encryption process in the clean machine.
qkG Filecoder using XOR cipher encryption and same encryption key used in each and every encrypted documents.
According to Trend Micro, Suppose we create a document containing the text “1234567890”. After closing the document on an infected machine, the odd characters get XORed with a corresponding character in the hardcoded password “I’m [email protected]! by [email protected]”, while each even character is left intact. The resulting encrypted document containing text “1234567890” is in the screenshot above.
“One of the tested samples contains a decryption routine.it’s not used within the malware body and accordingly doesn’t work. This malware can also be construed as malware still in development.”
Also, Researchers found a bitcoin address that is used along with this variant. But it seems no transaction has been performed.
While not particularly pervasive regarding impact, qkG’s unique use of malicious macros is still notable. And like other ransomware families, we expect this technique to be rehashed, broadened, and repurposed for other cyber attacks.
Disabling macros significantly reduces the risk of macro-based malware such as qkG. Trend Micro said.