SAN FRANCISCO — Make no mistake: It’s a shot across the bow of the online security industry.

Starting Monday, corporate security officers will be able to measure the effectiveness of major security products — a tool the industry has been sorely lacking. NSS Labs, an independent security testing company, has developed a testing service that will allow corporations to see how vendors stack up, including which real threats their products are blocking, and which they are not.

That kind of basic benchmarking is long overdue in an industry crowded with security firms that love to claim their products catch all the threats their competitors do not. In truth, if corporations could sue security software manufacturers for failing to catch data breaches the way patients can sue medical practitioners for malpractice, the security industry would have gone bankrupt long ago.

NSS Labs pulls in real threats it collects in “honey pots” — alluring traps they set up on the Internet that allow researchers to study intruders’ tactics while attackers break into what they believe is a real system. The company then tests those threats against security defenses from some of the biggest names in the business, including Cisco, Hewlett-Packard, McAfee and Symantec.

The offering is sure to put security vendors on notice. The end goal, said Vikram Phatak, chief executive of NSS Labs, is to offer real-time information to chief security officers in much the same way that Bloomberg terminals offer real-time financial information to analysts.

Until now, NSS Labs and others tested security products and released one-time reports. But those tests, often performed by the security vendors themselves, were often biased or unreliable because they were using canned threats. The new offering from NSS Labs allows security officers to test products in real time through a service that does not sell security products.

This kind of benchmarking is sure to shake up an industry that is loathe to admit it doesn’t catch everything. NSS Labs got a taste of that kind of backlash last year, after it released a test of various breach-detection systems, which found that FireEye, then the darling of the breach detection space, underperformed similar offerings from Cisco, General Dynamics and Trend Micro. NSS Labs actually issued a grade of “caution” to customers who used FireEye’s web and email malware protection systems.

That set off an unusual tit-for-tat between the testing service and FireEye after Manish Gupta, a FireEye executive, criticized NSS Labs’ testing service in a blog post. (NSS Labs researchers responded in their own blog post, “Don’t Shoot the Messenger.”) But the episode had a real impact on FireEye. The company’s stock price, which had been trading at $65 before NSS Labs released its study, tumbled to $40 and has hovered there ever since.