The malicious document downloads and executes a component that attempts to determine if the operating environment is a virtualized one, like an antivirus sandbox or an automated malware analysis system, by waiting to see if there’s any mouse activity before initiating the second attack stage. Mouse click monitoring is not a new detection evasion technique, but malware using it in the past generally checked for a single mouse click, Rong Hwa said. BaneChant waits for at least three mouse clicks before proceeding to decrypt a URL and download a backdoor program that masquerades as a technology by performing multibyte XOR encryption of executable files, masquerading as a legitimate process, evading forensic analysis by using fileless malicious code loaded directly into the memory and preventing automated domain blacklisting by using redirection via URL shortening and dynamic DNS services, he said.
For example, during the first stage of the attack, the malicious document downloads the dropper component from an ow.ly URL. The rationale behind using this service is to bypass URL blacklisting services active on the targeted computer or its network, Rong Hwa said. This is an attempt to trick users into believing that the file is part of the Google update service, a legitimate program that’s normally installed under “C:Program FilesGoogleUpdate”