Reuters alleged that Kaspersky researchers were assigned to work for months at a time on "sabotage projects" to reverse-engineer competitors' virus detection software to find out how to fool them into flagging clean files as malicious.
However, Kaspersky has rubbished the report in a detailed blog post. "The reality is that the Reuters story is a conflation of a number of facts with a generous amount of pure fiction," he said.
"The article, filled with sensational - false - allegations, claims Kaspersky Lab creates very specific, targeted malware, and distributes it anonymously to other anti-malware competitors, with the sole purpose of causing serious trouble for them and harming their market share.
"They forgot to add that we conjure all this up during steamy banya sessions, after parking the bears we ride outside."
The allegations, made by two anonymous former employees, claimed that Kaspersky Lab, which currently has 400 million users and 270,000 corporate clients, was engaged in a secret campaign to ruin smaller competitors.
The comments from Kaspersky echo those made by the company in a statement to V3 last week when the Reuters report was first published.
"Contrary to allegations made in a Reuters news story, Kaspersky Lab has never conducted any secret campaign to trick competitors into generating false positives to damage their market standing. Such actions are unethical, dishonest and illegal," the firm said.
"As a member of the security community, we share our threat intelligence data and IOCs on advanced threat actors with other vendors, and we also receive and analyse threat data provided by others. Although the security market is very competitive, trusted threat data exchange is a critical part of the overall security of the entire IT ecosystem."
Kaspersky said that the accusations from "disgruntled ex-employees" are "meritless and simply false".
He explained that the security firm conducted an experiment in 2012 by uploading 20 non-malicious files to VirusTotal, a free service that scans for malware, to test for false positives.
"We conducted the experiment to draw the security community's attention to the problem of insufficiency of multi-scanner-based detection when files are blocked only because other vendors detected them as being malicious, without actual examination of the file activity," he said.
The former employees alleged that Kaspersky Lab injected common PC files with bad code to make them look malicious when uploaded to VirusTotal. However, Kaspersky Lab denied this and said that it has itself been the victim of such a campaign in the past.
"In 2012, Kaspersky Lab was among the companies affected by an unknown source uploading bad files to VirusTotal, which led to a number of incidents with false-positive detections," the firm told V3.
"To resolve this issue, in October 2013, during the VB Conference in Berlin, there was a private meeting between leading antivirus vendors to exchange the information about the incidents, work out the motives behind this attack and develop an action plan. It is still unclear who was behind this campaign."
Meanwhile, Kaspersky took to Twitter to publicly rubbish the Reuters story.
Liam O'Murchu, reverse engineer and security researcher at Symantec, who investigated the original malware claims, also took to social media to voice his surprise at the Reuters report.
We had investigated these attacks but could not find out who was behind them. We had some suspects, Kaspersky was not one of them.— Liam O'Murchu (@liam_omurchu) August 14, 2015
Stefan Tanase, senior security researcher at Kaspersky Lab, hit out at the sources of the Reuters story.
note to self: when I publish my next APT report, I'll make sure to quote at least two anonymous sources, for added credibility.— Stefan Tanase (@stefant) August 14, 2015
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