An IT security product company warns that “invisible” targeted cyber attacks are using only legitimate software. They are penetration-testing and administration tools as well as the PowerShell framework for task automation in Windows – dropping no malware files onto the hard drive, but hiding in the memory.
According to Kaspersky Lab, this combined approach helps to avoid detection by whitelisting technologies, and leaves forensic investigators with almost no artefacts or malware samples to work with. The attackers stay around just long enough to gather information before their traces are wiped from the system on the first reboot.
At the end of 2016, Kaspersky Lab reports that it was contacted by banks in CIS which had found the penetration-testing software, Meterpreter, now often used for malicious purposes, in the memory of their servers when it was not supposed to be there. Kaspersky Lab discovered that the Meterpreter code was combined with a number of legitimate PowerShell scripts and other utilities. The combined tools had been adapted into malicious code that could hide in the memory, invisibly collecting the passwords of system administrators so that the attackers could remotely control the victim’s systems. The ultimate goal appears to have been access to financial processes.
The IT lab has since uncovered that these attacks are hitting more than 140 enterprise networks in a range of business sectors; most victims are in the USA, France, Ecuador, Kenya, the UK and Russia.
Sergey Golovanov, Principal Security Researcher at Kaspersky Lab, said: “The determination of attackers to hide their activity and make detection and incident response increasingly difficult explains the latest trend of anti-forensic techniques and memory-based malware. That is why memory forensics is becoming critical to the analysis of malware and its functions. In these particular incidents, the attackers used every conceivable anti-forensic technique; demonstrating how no malware files are needed for the successful exfiltration of data from a network, and how the use of legitimate and open source utilities makes attribution almost impossible.”
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