Disguised Browsers

Many browsers disguise themselves by presenting userAgent strings which mis-report the browser name or version. Browsers may do this so that: 1 sites will render pages as popular browsers will; 2 sites which try to sabotage enemy browsers will fail to do so; or 3 user-hostile governments can’t tell that the user’s browser circumvents government oversight.

Examples are:

1. Internet Explorer & Firefox: these browsers report the major version numbers, but not the complete version vec­tors including the minor version numbers.

   An example is Firefox 94.0.2, which wrongly reports itself as being Firefox 94.0.

   There appears to be no good reason for browsers to do this. Most browsers don’t.

2. Opera: many archaïc, na­ïve brow­ser snif­fers have failed to detect Opera correctly, resulting in pages being rendered poorly. Opera Software therefore repeatedly changed the Opera userAgent string in archaïc versions of Opera, disguising it as a popular browser, so that naïve brow­ser snif­fers would instead identify Opera as one of the popular browsers.

   This is not an issue with well-designed web pages or competent browser sniffers.

3. Opera: many archaïc, na­ïve brow­ser snif­fers assumed that browser version vec­tors would begin with 1-digit numbers, so that, when a vector beginning with a 2-digit number appeared — i.e. Opera 10.x — the poor brow­ser snif­fers reported Opera 10 as Opera 1, resulting in pages being rendered poorly. Opera Software therefore set the Opera userAgent string to report Opera 10 as Opera 9.8x, so that the poor brow­ser snif­fers would identify Opera 10 as Opera 9.

   This is not an issue with well-designed web pages or competent browser sniffers.

4. Vivaldi: enemies of Vivaldi such as FaceBook, Google, and Microsoft sabotaged Vivaldi by presenting broken code to Vi­val­di, or re­fus­ed to allow Vivaldi users to use their sites. Consequently, starting with Vivaldi v2.10, Vivaldi Tech­no­lo­gies began pre­sent­ing the same userAgent string as a Chrome browser, ensuring that its enemies could not sabotage Vivaldi without also sa­bo­tag­ing Chrome. Un­for­tu­nate­ly, this means that 1 good, honest brow­ser snif­fers like the one used by my sites will fail to identify Vivaldi users; and 2 browser statistics won’t count the number of Vivaldi users, mak­ing Vivaldi appear to be unpopular. More

   Even if such a problem may not exist today, it has been so common for major companies to sabotage enemy browsers in the past, that there is still a serious risk that such a problem could appear in the future.

5. Brave: it’s possible that enemies of Brave would also try to sabotage it as well, however Brave currently presents the same userAgent string as Chrome, perhaps to prevent such a problem.

   Even if such a problem may not exist today, it has been so common for major companies to sabotage enemy browsers in the past, that there is still a serious risk that such a problem could appear in the future.

6. TOR: this reports that it is Firefox — likely Firefox ESR — so that user-hostile governments will not realize that the user is using a browser which cirumvents government oversight.

 

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