The Opera attack from last week, which saw a malware signed as a certificate, posed as an Opera update.
According to Trend Micro, it obtained a sample of the malware that bears the outdated Opera certificate and once executed, it steals crucial information from certain FTP clients or file managers including user names, passwords and server names. Trend Micro detected this malware as TSPY_FAREIT.ACU.
It also said that the malware gathers more information from browsers and collects login data to access accounts or even initiate unauthorised transactions. “They can also profit from these stolen data by selling these to the underground market,” it said.
Opera estimates that several thousands of Windows users are affected as a result of their installed Opera software automatically installing the said malware bearing the outdated certificate. To address this issue, Opera has promised to release a new version of its browser.
Opera said that the attack last week was achieved after attackers accessed and stole at least one certificate that they used to sign malware. Sigbjorn Vik, who works in quality assurance at Opera Software, said that the hackers did not compromise any data belonging to users, and that the infection has been neutralised.
Vik also claimed that the certificate was "old and expired", and that for a 36-minute period on 19th June, "a few thousand" Windows users who were running the browser, may have automatically received and installed the malware.