Adobe is set to patch the perennially vulnerable Flash Player after an attack on the security firm Hacking Team revealed an unpatched "zero day" flaw in the software.

The flaw was discovered after hackers leaked some 400GB worth of data from white hat hacking company, which has courted controversy for selling spyware to governments around the world.

Since then Adobe has confirmed it is aware of the reports, adding that it expects to patch the "critical vulnerability" sometime on Wednesday.

In the wake of the attack, Hacking Team revealed it has no plans to fire anybody from its staff, and claims that no customers have abandoned the company despite the bad press generated from the hack.

"[It] was a very sophisticated operation," Eric Rabe, a spokesman for the company, told Ars Technica in a phone interview.

"This wasn’t a lone hacker working in an upstairs bedroom, this is a much more sophisticated attack than that. Businesses are frequently the subject of such attacks like this and sometimes they’re successful."

The hack has revived criticism of the Italian firm for its cooperation with oppressive governments such as Sudan, part of a wider-ranging argument about the use of security tools to protect privacy around the world.

Ken Westin, Senior Security Analyst at Tripwire, told CBR: "As many governments move to try and control malware and offensive security tools, some have been caught with their own hands in the cookie jar, leading many to wonder how and why governments and agencies listed as Hacking Team clients are using these tools and if they are doing so lawfully."

"Given the depth and amount of data compromised in this breach, it will reveal a great deal about the market for offensive tools designed for espionage with a great deal of fallout and embarrassment for some organisations."