One of the mysteries of the huge increase in direct traffic this month coming from IE7 browsers was solved when it was determined that AdRoll retargeting was one of the focuses of the spam bot.

However, the issue is a lot more widespread than initially believed.  In an email to The SEM Post, Stephanie Sibal stated that it “impacted a range of ad tech companies, including AdRoll, which resulted in invalid traffic being driven to a portion of our customers’ websites.”

Since AdRoll wasn’t the only network targeted by this retargeting bot, if you use any kind of retargeting (aka remarketing), you will want to have a close look at your logs for the month of July (starting around July 7th) to see if you were affected.  It is unknown which other networks are affected and if they are proactively issuing refunds to those affected.  The retargeting spam bot was largely noticed first by AdRoll advertisers as it is one of the largest real time bidding purchasers.

They also plan to work with others to help filter some of this traffic before it ever hits advertiser accounts.

We’ve confirmed reports of other networks being impacted as well, so we are working with our supply partners to have checks in place to better pre-filter suspicious publishers in the future. This work should benefit the entire digital ad ecosystem.

As far as AdRoll customers, they determined that only 394 advertisers had an impact of above $50 and that the vast majority of advertisers were impacted by less than $10 total.

They have also taken additional steps to prevent this kind of attack impacting AdRoll in the future:

• All advertisers with any amount of invalid traffic have been proactively credited the appropriate amount
• All invalid traffic data has been removed from our reporting
• We’ve permanently blacklisted the sites generating the invalid traffic and enhanced our algorithms to better detect these types of attacks in the future
• Our dedicated Trust and Safety team will continue to keep watch of issues like this and will receive better alerts when issues occur, so we can notify our customers

Here is a copy of the AdRoll email to customers who were impacted by the bot.

Subject: Safeguarding your AdRoll account from invalid traffic

Dear [customer name redacted],

We recently noticed a spike in your site visitors and determined the source to be an invalid traffic issue impacting various ad companies over the last two weeks, including AdRoll.

We have swiftly addressed vulnerabilities within our system and we are working closely with our supply partners to ensure that your display campaigns are driving only quality traffic to your website. While only a small fraction of impressions (less than 1%) have been affected by this invalid traffic, we have taken the following actions to rectify and ensure the appropriate systems are in place to prevent scenarios like this in the future:

• AdRoll has proactively issued the appropriate account credits to all of those advertisers affected
• Publisher websites found to be generating the invalid traffic have been permanently removed from our network
• We have a team in place dedicated to enhancing our algorithms to better detect these types of attacks in the future

Mitigating against invalid traffic is an ongoing challenge shared by all participants in the online advertising industry– but you can rest assured that AdRoll always has our advertisers’ best interests in mind. We are hyper-focused on developing innovative methods to keep us on the cutting edge of traffic quality and performance.

We apologize for any inconvenience this may have caused, and we thank you for your understanding and patience in this matter. Please don’t hesitate to reach out to us at delight@adroll.com with any questions or feedback.

Sincerely,
Your AdRoll Customer Delight Team