The clearest most specific summary explanation I have seen is: https://arstechnica.com/information-technology/2017/10/kaspersky-reportedly-modified-its-av-to-h

The clearest most specific summary explanation I have seen is: https://arstechnica.com/information-technology/2017/10/kaspersky-reportedly-modified-its-av-to-help-russia-steal-nsa-secrets/?itm_source=parsely-api https://arstechnica.com/information-technology/2017/10/kaspe... Note the Israeli findings and the months of experiments by US intel agencies after the fact and the conclusions they drew. The initial counterargument from Kaspersky (which seems to address some but not other concerns raised in the above link) apparently was something like the following: https://arstechnica.com/information-technology/2017/11/kaspersky-yes-we-obtained-nsa-secrets-no-we-didnt-help-steal-them/?itm_source=parsely-api https://arstechnica.com/information-technology/2017/11/kaspe... Both the above are from 2017 in the months after the issues about Kaspersky concerns first came to light. This triggered the ban of Kaspersky from US government computers back then. Not sure what info may or may not have come to light since then but most people are not even aware of the above. The official 2024 USG reasons which impact are outlined in four bullets in the press release here: https://www.bis.gov/press-release/commerce-department-prohibits-russian-kaspersky-software-us-customers https://www.bis.gov/press-release/commerce-department-prohib... which in turn points to an ODNI (Office of the Director of National Intelligence) public-facing PDF/slide of the reasons: https://www.dni.gov/files/CTIIC/documents/products/Kaspersky_Lab_Products_Expose_US_Users_Data_to_Russian_Intelligence_Collection-June2024.pdf https://www.dni.gov/files/CTIIC/documents/products/Kaspersky... and the US Commerce department's findings at https://oicts.bis.gov/pdfs/AppendixA.pdf https://oicts.bis.gov/pdfs/AppendixA.pdf (mostly blacked out but you get a sense of the back-n-forth reasoning justifying what steps short of a ban could be taken at least a little bit) and the Commerce Department Kaspersky FAQ at https://oicts.bis.gov/kaspersky/faq/ https://oicts.bis.gov/kaspersky/faq/ I have no first/secondhand knowledge of any of this stuff but this is what my curiosity turned up when I went poking around. Having observed corporate US security practices, my perception is that a lot of protection involves scanning things using very low-level OS and/or network techniques. Remember that phrase "who guards the guardians? ( https://en.wikipedia.org/wiki/Quis_custodiet_ipsos_custodes%3F https://en.wikipedia.org/wiki/Quis_custodiet_ipsos_custodes%... ) The Kaspersky ban by the US Commerce department appears to be essentially a concession that "who scans the scanners?" is not something the US can particularly do for products with the type of low-level access provided to AV/malware products, particularly products from entities with a concrete history of specific adverse (2014-2017) behavior from a particularly skilled hostile country (in this case Russia).