A malicious comma-separated values (CSV) file is now used to infect devices with the malware BazarBackdoor.
The malware BazarBackdoor was developed by the TrickBot group and gives attackers remote access to an internal file that can be used to spread laterally within a network.
A CSV is considered harmless because it is a simple text with no executable code. However, a Dynamic Data Exchange (DDE) feature in Microsoft Excel can be used to execute commands whose output is inputted into the open table, including CSV files.
The phishing campaign disguised as the Payment Remittance Advice provides links to remote websites that download a CSV file with names similar to ‘document-21966.csv.’
This text file contains a strange WMIC call in one of the columns of data called a DDE function. The DDE uses WMIC to create a new PowerShell process, which opens a remote URL, which contains another PowerShell command, which is then executed.
However, the process of installing the malware is not complete without users confirming the execution of the DDE function.
For more information read the original story in BleepingComputer.