Cybersecurity firm Kaspersky Lab has filed a lawsuit targeting the second of two federal bans on its wares. The latest suit goes after language in a defence law explicitly blocking the purchase of Kaspersky products. An earlier suit targets a Homeland Security directive doing the same thing.

Kaspersky Lab filed a second lawsuit in district court this time to overturn a congressionally-mandated ban of its software and services. Kaspersky already filed suit in December against the Department of Homeland Security’s policy directive from last fall that required agencies to remove the company’s products from federal networks. Kaspersky Lab has now said the provision in the 2018 Defense Authorisation bill banning it from federal networks is unconstitutional.

The company asked the court to stop the implementation of ban, which is expected to start in October.

Kaspersky’s lawyers say that under the Constitution’s Bill of Attainder Clause, Congress is forbidden “from enacting laws which impose individualised deprivations of life, liberty, and property and inflict punishment on individuals and corporations without a judicial trial.”

“No evidence has been presented of any wrongdoing by the company, or of any misuse of its products … We continue to offer our full cooperation to government agencies and others with cybersecurity concerns collaboratively and openly through our Global Transparency Initiative," the outfit's brief's said.