Kaspersky Lab, the antivirus house, now claims that the US government's ban on its products amounts to punishment without trial.

In court filings made late last year Kaspersky said it was intending to use the US Administrative Procedure Act to get the ban declared unconstitutional. Now, according to local reports, the Russian company is bringing the US Constitution's Bill of Attainder clause, which forbids punishment without trial, into play to bolster its legal arguments.

The American Department of Homeland Security (DHS) banned the use of Kaspersky products in September 2017 across the entire US government.

Controversy had arisen in American governmental circles that a National Security Agency contractor (NSA – a snooping agency like Britain's GCHQ but better scrutinised) who took his work home with him had leaked software exploits intended to be used for hacking by US government agents thanks to an unintentional upload to the Kaspersky cloud. The Americans convinced themselves that Russian-owned Kaspersky had given access to these exploits to Kremlin intelligence services, though the company denies this.

Not long after the ban, GCHQ in the UK issued a similar order to government departments over here for information classified as Secret or above.

Kaspersky's PR firm told The Register today: "Kaspersky Lab maintains that the DHS decision is unconstitutional and relied on subjective, non-technical public sources, such as uncorroborated and often anonymously sourced media reports, related claims, and rumors. Furthermore, DHS has failed to provide the company adequate due process to rebut the unsubstantiated allegations underlying the BOD and has not provided any evidence of wrongdoing by the company."

America is becoming increasingly allergic to foreign tech companies' wares, on the grounds that what its spies euphemistically call "computer network exploitation" might come home to roost. ®