Security experts recently detected a significant “surge” in Sasfis activity linked to the nefarious Asprox spambot.
“While Asprox has been around for some time, it has been silent for more than a year,” explained Fortinet spokesperson Derek Manky.
“The Asprox module [we] dissected was intended to be used for an email seeding campaign. The emails contained zipped executable attachments, disguised as fax copies.
“And the attachment was a copy of Sasfis, which would download Asprox in order to send more spam on the freshly infected machine.”
Manky added that FortiGuard had also detected and downloaded a “sniffer module” (variant) designed to scan traffic on TCP ports 21, 25 and 110 (FTP, SMTP and POP3).
“Traffic on these ports would be processed by the module into encrypted data sets and sent via HTTP POST to a command and control server located in Europe.
“[Now], stolen FTP credentials can be quite valuable and are often used to hijack Web servers.
“[But] the variant was also observed downloading the TotalSecurity ransomware suite, which has been high on our malware radar for a number of weeks.”