A phishing effort that was distributing three fileless malware onto a victim's device was detailed by cybersecurity experts at Fortinet's FortiGuard Labs. AveMariaRAT, BitRAT, and PandoraHVNC trojan viruses are spread by users who mistakenly run malicious attachments delivered in phishing emails. The viruses are dangerously capable of acquiring critical data from the device.
Cybercriminals can exploit the campaign to steal usernames, passwords, and other sensitive information, such as bank account numbers. BitRAT is particularly dangerous to victims because it can take complete control of infected Windows systems, including viewing webcam activity, listening to audio through the microphone, secretly mining for cryptocurrency that is sent to the attackers' wallet, and downloading additional malicious files.
The first phishing mail appears to be a payment report from a reputable source, with a brief request to view a linked Microsoft Excel document. This file contains dangerous macros, and when you open it, Microsoft Excel warns you about using macros. If the user disregards the warning and accepts the file, malware is downloaded. The malware is retrieved and installed onto the victim's computer using Visual Basic Application (VBA) scripts and PowerShell. For the three various types of malware that can be installed, the PowerShell code is divided into three pieces. This code is divided into three sections and employs the same logic for each virus:
- A dynamic mechanism for conducting GZip decompression is included in the first "$hexString."
- The second "$hexString" contains dynamic PowerShell code for decompressing the malware payload and an inner.Net module file for deploying it.
- The GZip-compressed malware payload is contained in the "$nona" byte array. The following PowerShell scripts are retrieved from the second $hexString and are used to decompress the malware payload in $nona and to deploy the malware payload into two local variables using the inner.Net module.
The study doesn't explain as to why the phishing email contains three malware payloads, but it's conceivable that with three different types of malware to deploy, the cybercriminals will have a better chance of gaining access to whatever critical information they're after.
Phishing is still one of the most prevalent ways for cyber thieves to deliver malware because it works – but there are steps you can take to avoid being a victim. Mysterious emails claiming to offer crucial information buried in attachments should be avoided, especially if the file requires users to allow macros first. Using suitable anti-spam and anti-virus software and training workers on how to recognize and report phishing emails, businesses may help workers avoid falling victim to phishing emails.
