Code capable of disabling software, known as "time bombs", could be introduced next year to trigger a shutdown when a user's licence expires.
Australian user groups have labelled a renewed push by vendors to adopt the Uniform Computer Information Transaction (UCITA) in the US a recipe for "mayhem".
Users fear use of the code by vendors could become pervasive if the controversial software law succeeds and is used to enforce licensing programs. The bug can be triggered without warning and send business systems crashing.
Vincent Teubler, managing director of VTR Consulting and organiser of Australia's annual user group open day, said vendors are simply making a grab for money. "I have absolutely no doubt that the vendors would be justly rewarded with significant additional licensing revenues if they proceed down this path," he said.
However, he said users could send a message to vendors that choose to adopt disabling software: "Don't buy it".
Andrew Hennell, System Administrators Guild of Australia (SAGE) president, said time-bombed software that cripples a corporation because its licence is out by a few days will do more damage to the vendor than anyone else.
"Could you imagine an entity the size of Telstra having its e-mail system grind to a halt because of a vendor-planted time bomb? The thought of code that could cripple an enterprise lurking just below the surface is not what an IT manager wants to have on the network," Hennell said.
"To secure ongoing revenue and licence renewals, software vendors need to invest in building customer relationships. Companies need and expect vendor support. Companies that choose to let their licences lapse will soon fall behind with outdated and unsupported software anyway, which is not a sustainable strategy."
The US Institute of Electrical and Electronic Engineers claims UCITA provisions give vendors the right to build in back doors, creating a potentially large shift in software licensing practices.
Alan Plastow, president of the International Association of IT Asset Managers, said the industry is pushing very hard for a mainframe licensing model, where users pay for software on a yearly basis. "That requires the use of automatic restraints, or it requires the use of a metering process," he said.
IDC analyst Steve McHale said the use of software restraints won't help vendors win contracts with large enterprises. "But such techniques could be attractive to vendors of pricey programs, such as engineering software systems," he said.
The proposed law also has liability-limiting provisions that protect vendors from mistakes.