Firefox Users Attacked Via Zero-Day Flaw

Firefox users this week attacked via a zero-day vulnerability in the browser, which Mozilla yesterday evening decided to release an emergency patch. Using the vulnerability, an attacker could seek to sensitive files on computer users and then upload to a server.

The attack was observed in the wild took place on a Russian news site. The exploit made sure that files were sent to a server in the Ukraine. This would especially be looking for files that were aimed at developers. For example, a search for subversion, s3browser and configuration files of FileZilla, .purple and Psi + account information as well as configuration files of eight different popular FTP clients. The exploit was both Linux and Windows users targeted. Mac users were not a target, but it could be attacked via the vulnerability.

Furthermore, the exploit does not leave any traces on the computer behind. Mozilla advises Firefox users on Windows or Linux using the aforementioned programs to change their passwords and keys there. Although the attack on a Russian website has been observed, Mozilla does not exclude that the exploit has also been used on other websites. Users of a AdBlocker may be protected from the exploit, depending on which filters they used. It therefore seems that the exploit via advertising is disseminated. Firefox, according to StatCounter after the popular Chrome browser, with a market share of 16.5%.

PDF viewer

The vulnerability is present in a mechanism that should ensure that JavaScript is separated from the PDF viewer in Firefox.The problem therefore was not present in Firefox for Android, because this browser does not have an embedded PDF reader.An attacker to execute arbitrary code via the vulnerability, for instance to install malware or take over the computer.

Mozilla still has the leak situation as critical, which is the highest rating for vulnerabilities in Firefox. Because of the vulnerability, users get the advice to go directly to Firefox 39.0.3 to upgrade . This can be done via the update mechanism of the browser or Mozilla.org .