Security firms are split about whether they will classify Phorm's targeting cookies as adware.

Kaspersky Lab, whose anti-virus engine is licensed to many other security vendors, said it would detect the cookie as adware. However, AVG, developer of the most widely used free of charge anti-virus scanner, said it would not detect Phorm's cookie even though the Czech firm's CTO Karel Obluk describes the technology as "borderline".

AVG has decided not to detect Phorm cookies. The reason for this is that the cookies themselves do not store information about browsing habits and visited pages.

In this instance it is the ISP that monitors your surfing and forwards the information to Phorm. It is not possible to use these cookies to identify the actual pages you browse without cooperation from your ISP. In addition to that, if we were to block Phorm cookies then we would prevent users from being able to unsubscribe from the service

We believe that Phorm lies just outside the boundaries of being classified as adware - they adhere to the recommendations laid down by the Anti-Spyware Coalition requiring user consent. A user must accept the user licence agreement to make the service active and they allow users to unsubscribe from the service.

AVG regards what Phorm is doing as borderline but we have to concede they have made every attempt to try to stay on right side of that line.

Our view is based on information from public sources - we have not had any direct insight into their technology.

AVG's worries about informed consent by ISP subscribers, reservations about Phorm's preferred approach of obliging users to opt-out, and a lack of engagement between Phorm and security suppliers are echoed across the industry.

If security firms add detection for Phorm then users running a scan would get a warning that their ISPs have dropped either a Phorm opt-in or an opt-out cookie onto their systems.

As previously reported, Trend Micro said there was a "very high chance" that it would add detection for the tracking cookies as adware. PC Tools echoed Trend's concerns about privacy and security, urging Phorm to apply an opt-in approach.

Specialist anti-spyware firm Sunbelt Software also expressed concerns, saying Phorm's tracking cookies were candidates for detection by its anti-spyware software.

While we don't generally consider cookies to be adware (adware is a form of locally installed software; cookies are mere inert data), our anti-spyware products do target "tracking" cookies used by online advertising networks to gather data about surfers' web usage across sites/domains because these types of cookies do pose potential privacy concerns. Phorm's cookies fall into this category and are candidates for being targeted by our anti-spyware applications.

Webroot, another prominent anti-spyware firm, reported difficulties at getting samples of Phorm's tracking cookies for evaluation purposes.

We are detecting earlier generations of this adware, and our research team is still researching this most recent version as it is challenging to get samples due to the closed nature of the distribution at the moment.

On a general note, we have a predefined set of criteria (mainly based on the properties and behaviour), which we are using to decide if a particular sample should be detected or not, and which are applied universally.

We polled a number of security firms on their attitudes to Phorm. We are waiting for responses from Symantec and McAfee, the two largest anti-malware vendors, as well as Check Point, which markets the popular Zone Alarm personal firewall. ®

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