Trickbot malware is a banking Trojan that has been around for a few years now, although its authors have recently developed a WannaCry ransomware-style worm module that allows it to spread much more rapidly.
The recent NotPetya attacks also included a similar module enabling the malware to be used in devastating attacks that wiped out entire systems.
This new method of speeding up the spread of malware takes advantage of a vulnerability in Windows Server Message Block, which is used to identify all vulnerable computers on a network that connect via the Lightweight Directory Access Protocol (LDAP).
Since the exploit is readily available, cybercriminals can use it in conjunction with malware to spread infections more effectively and quickly. Worms were once popular, although their use has died out. The use of worm-like elements with the WannaCry and NotPetya attacks has shown just how effective they can be, and also served as a reminder of why they were popular in the first place.
Far from isolated malware variants, we could be about to see a rise in the use of worm-like modules. Fortunately, for the time being at least, the worm module in Trickbot malware does not appear to be fully operational. That said, the malware is constantly being redeveloped so it is probable the flaws will be fixed soon.
The malware can gain access to online banking accounts enabling the attackers to empty bank accounts. It is fast becoming one of the most prevalent banking Trojans, according to IBM X-Force. It is currently being used in targeted attacks on organizations in the financial sector around the world, with recent campaigns targeting banks in the UK and United States. The ability to spread throughout a network rapidly will make it much more dangerous.
Aside from the new worm-like module another change has been detected. PhishMe reports that it has identified a change to how the Trojan is distributed. Attacks have occurred via malvertising campaigns this year that redirect web users to sites hosting the Rig exploit kit, although Trickbot is primarily distributed via spam email sent via the Necurs botnet.
The latest change to the Trickbot malware campaign is helping the threat actors to evade anti-virus solutions. Previously, the Trojan has been installed via macro scripts in specially crafted office documents. The latest campaign update sees the attackers use a Windows Script Component (WSC) containing XML-format scripts. The same delivery mechanism has also been used to deliver GlobeImposter ransomware.