Microsoft uncovered a new campaign with a sophisticated infection chain delivering notorious FlawedAmmyy RAT as a final payload. The attack starts with an email that contains .XLS attachments and the contents of the email in the Korean language.
Previous campaigns that involve FlawedAmmyy RAT are carried out by TA505 threat actors, upon successful execution of backdoor let an attacker to control the machine remotely, manages the files, captures the screen.
Malicious .XLS file delivered through email, when the file executed it automatically runs a macro function that runs Windows Installer msiexec.exe used for download & installing MSI and MSP packages.
The downloaded MSI archive contains a digitally signed executable that is extracted and executed, it decrypts and runs another executable wsus.exe in memory, which in turn decrypts and runs the final payload in the memory.
The final payload that delivered directly in memory is the FlawedAmmyy, according to Microsoft Security Intelligence. The FlawedAmmyy digitally signed using a code signing certificate issued Thawte to the company Dream Body Limited. It appears the rat was signed and timestamped on June 19 and the samples detected on June 22.
The FlawedAmmy RAT functions
Earlier this year TA505 distributed FlawedAmmyy RAT via weaponized MS Excel documents with malicious Excel 4.0 macro which is hard to detect by standard security controls.
Last October Cybercriminals used IQY Files to deliver FlawedAmmyy malware and executed the backdoor through PowerShell Process.
IoCs (SHA-256):
0e91e6e17f8c8e2f1ae29e13f116c8611cb7679607695eed355025295fb1999a (.xls),
19d8993c742fc1a7c651ab3dba4d8c7f5e142a8421e22dd0c20c2db2d5dccffd (MSI),
cb114123ca1c33071cf6241c3e5054a39b6f735d374491da0b33dfdaa1f7ea22 (digitally signed executable inside MSI)
c2c6f548fe6832c84c8ab45288363b78959d6dda2dd926100c5885de14c4708b (digitally signed wsus.exe),
6860de46fdea393bd48ca000ecff4047920a56728b7945f95a6ca0801c278097 (FlawedAmmyy RAT)
You can follow us on Linkedin, Twitter, Facebook for daily Cybersecurity updates also you can take the Best Cybersecurity course online to keep yourself updated.
Some router models have identified a security vulnerability that allows attackers to bypass authentication. To exploit this vulnerability, an attacker…
Hackers often target CrushFTP servers as they contain sensitive data and are used for file sharing and storage. This makes…
DDoS attacks are a significant and growing risk that can overpower websites, crash servers, and block out authorized users with…
Hackers have leveraged an old Microsoft Office vulnerability, CVE-2017-8570, to deploy the notorious Cobalt Strike Beacon, targeting systems in Ukraine.…
In a historic move, Microsoft has made the source code for MS-DOS 4.0, one of the most influential operating systems…
A new attack campaign has been discovered to be employed by the FROZEN#SHADOW, which utilized SSLoad malware for its operations…