The only way I'm aware that you could stop this f.txt file from being downloaded again in the future would be to block the most common domains that appear to be serving this exploit.The f.txt download just means you were protected from a recent potential attack with this exploit and you should have no reason to believe you were compromised in any way. This is why various users online are confused thinking they fixed the issue or somehow affected it by uninstalling this program or running that scan, when in fact it is all unrelated.
For example, the advertisement domain ad. probably serves out hundreds of thousands of different ads and only a small percentage likely contain malicious content. Note that this issue will be random and intermittent in nature because even visiting the same pages consecutively will often produce different ad content.
This has the annoyance of causing the browser to automatically download a file called f.txt that you didn't request-but it is far better than your browser automatically running a possibly malicious Flash file. One component of the ad-hoc mitigation implemented by these website owners was to force the HTTP Header Content-Disposition: attachment filename=f.txt on the returns from JSONP endpoints. Among the sites to do so: Google, Youtube, Facebook, Github, and others. Adobe has released at least 5 different fixes over the past year while trying to comprehensively fix this vulnerability, but various major websites also introduced their own fixes earlier on in order to prevent mass vulnerability to their userbases.This allows bypassing of the "same-origin policy" and can permit hackers a variety of exploits.
Some time around the summer of 2014, IT Security Engineer Michele Spagnuolo (apparently employed at Google Zurich) developed a proof-of-concept exploit and supporting tool called Rosetta Flash that demonstrated a way for hackers to run malicious Flash SWF files from a remote domain in a manner which tricks browsers into thinking it came from the same domain the user was currently browsing.This issue appears to be causing ongoing consternation, so I will attempt to give a clearer answer than the previously posted answers, which only contain partial hints as to what's happening. Wondering if anybody else had experienced / insight. I assume it is a content-disposition related bug with some of the JS files loaded on the page, and will clear up in a future patch. In looking up the issue on Google, others have experienced the same, but I have not found any resolution or understanding of why this is happening. I do not have any adblock plugins installed.į.txt contains a few lines of JavaScript.starting with: if (!window.mraid) document.write('\x3ca target\x3d\x22_blank\x22 href\x3d\x22\x3dAKAOjsvDhmmoi2r124JkMyiBGALWfUlTX-zFA1gEdFeZDgdS3JKiEDPl3iIYGtj9Tv2yTJtASqD6S-yqbuNQH5u6fXm4rTh圜Z0plv9SXM-UPKJgH4KSS08c97Eim4i45ewgN9OoG3E_ 111, variably when I visit certain Google related sites (like and get presented with an ad before the video), the browser downloads a file named f.txt.