A new version of Trojan Astaroth has the ability to exploit vulnerable processes in anti-virus software and services. Researchers of Cyctres' nocturnus team reported today in a publication at their blog that the variant is able to use security software modules to steal credentials and personal data on the internet.
In its latest form, Astaroth is used in spam campaigns throughout Brazil and Europe, managing thousands of infections by the end of 2018. Malicious software spreads through .zip files and malicious links.
Astaroth Trojan: How It Works
Researchers report that the Trojan disguises itself as a JPEG, .GIF, or something archive χωρίς επέκταση για να αποφύγει την ανίχνευση από εφαρμογές ασφαλείας. όταν εκτελείται σε ένα machine. Για να ολοκληρωθεί η λήψη του κακόβουλου λογισμικού χρησιμοποιείται το εργαλείο Microsoft Windows BITSAdmin από ένα διακομιστή εντολών και ελέγχου (C2). Μετά την λήψη, το κακόβουλο πρόγραμμα τρέχει ένα XSL script που δημιουργεί ένα κανάλι με τον διακομιστή C2. Το script, φέρεται να περιέχει λειτουργίες που βοηθούν την κακόβουλη εφαρμογή να κρυφτεί από security software, but also to leverage the BITSAdmin tool to download malicious payloads, from a separate C2 server. Previous variants of the Trojan would then try to find antivirus programs, and if Avast was present on an infected system, the malware would stop working. However, the new Astaroth can fool your antivirus program and add "a malicious module to one of its processes," according to the researchers. If it detects Avast, it breaks the Avast Software Runtime Dynamic Link Library, which runs modules for Avast with the aswrundll.exe process. The executable file – which looks like Microsoft's rundll32.exe – can run DLLs by calling its exported functions. The Trojan first appeared in attacks against users in South America during 2017. The malware is capable of stealing information from target systems such as passwords access, data from the keyboard and any content that was on the clipboard. In addition, Astaroth is also able to monitor calls if installed on a suitable device and terminate various processes. The new malware also uses a fromCharCode() deobfuscation method to hide code execution. Last month, a new study published by the Malwarebytes reported that Trojan and backdoor attacks have more than doubled since the previous year. Also, spyware attacks have increased in frequency, recording an increase of 142% over the same period.
