Any additional information been found on the user?
as long as you’re up to date on everything here: https://boehs.org/node/everything-i-know-about-the-xz-backdoor
the only additional thing i’ve seen noted is a possibilty that they were using Arch based on investigation of the tarball that they provided to distro maintainers
Can’t confirm but unlikely.
Via https://boehs.org/node/everything-i-know-about-the-xz-backdoor
They found this particularly interesting as Cheong is new information. I’ve now learned from another source that Cheong isn’t Mandarin, it’s Cantonese. This source theorizes that Cheong is a variant of the 張 surname, as “eong” matches Jyutping (a Cantonese romanisation standard) and “Cheung” is pretty common in Hong Kong as an official surname romanisation. A third source has alerted me that “Jia” is Mandarin (as Cantonese rarely uses J and especially not Ji). The Tan last name is possible in Mandarin, but is most common for the Hokkien Chinese dialect pronunciation of the character 陳 (Cantonese: Chan, Mandarin: Chen). It’s most likely our actor simply mashed plausible sounding Chinese names together.
They’re more likely to be based in Eastern Europe based on the times of their commits (during working hours in Eastern European Time) and the fact that while most commits used a UTC+8 time zone, some of them used UTC+2 and UTC+3: https://rheaeve.substack.com/p/xz-backdoor-times-damned-times-and
It is also hard to be certain as they could be a night owl or a early riser.
Just because somebody picked a vaguely Chinese-sounding handle doesn’t mean much about who or where.