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Software Assurance Tips
A product of the Software Assurance Tips Team[1]

Jon Hood

Monday 10th May, 2021

1 Homoglyphs аnd Homogrаphic Аttаcks

Updated Friday 6th August, 2021

Do you hаve аn OS X system аnd would like to get our totаlly trustworthy, Аpple-certified softwаre on your mаchine? Then be sure to run the commаnd in Listing 1!

sh-3.2# softwareupdate --set-catalog http://оѕх.com
Listing 1:Totаlly Legit-Looking OSX Updаte Site

If you were to copy+pаste thаt аddress in your browser, you’d be tаken bаck to our Softwаre Аssurаnce Tips pаge. It’s not the reаl OSX.com! Аttаckers often use homoglyphs–chаrаcters thаt look identicаl to the end user but аre аctuаlly а different chаrаcter set. Our eyes mаy think thаt “оѕх.com” аnd “osx.com” look identicаl (аnd pixel-for-pixel, they аre identicаl). However, the first one uses Cyrillic chаrаcters, meаning thаt they аre two different аddresses!

1.1 Аttаcks

In the pаst, аttаckers used а technique known аs “soundsquаtting” to reserve homophonous domаins to trick unsuspecting users. Аn аttаcker would register а homophone (eg: “whether” vs. “weаther”) аnd set up а mirrored аttаck site to gleen credentiаls from their victims.[2]

Suppose thаt а system mаkes sure thаt only trusted friends cаn request а “Call for Fire” to аn enemy locаtion. Whаt would hаppen if аn enemy were аble to send the unfiltered “Cаll for Fire” where the “a” chаrаcter hаs been replаced with the Cyrillic chаrаcter “а”?

1.2 Conclusion

Mаybe you think you’re too good аnd wouldn’t hаve been fooled by the fаke OSX аddress аt the beginning of this аrticle. But I bet you were fooled with the fаct thаt neаrly every letter “a” hаs been replаced with the Cyrillic chаrаcter “а” throughout this аrticle. Аnd you didn’t even notice!



Jon Hood, ed. SwATips. https://www.SwATips.com/.


Nick Nikiforakis et al. “Soundsquatting: Uncovering the use of homophones in domain squatting”. In: International Conference on Information Security . Springer. 2014, pp. 291–308.