Cybercriminals are abusing a widespread lack of authentication within the customer support platform Zendesk to flood focused e mail inboxes with menacing messages that come from lots of of Zendesk company prospects concurrently.
Zendesk is an automatic assist desk service designed to make it easy for folks to contact corporations for buyer help points. Earlier this week, KrebsOnSecurity began receiving hundreds of ticket creation notification messages by way of Zendesk in speedy succession, every bearing the identify of various Zendesk prospects, similar to CapCom, CompTIA, Discord, GMAC, NordVPN, The Washington Submit, and Tinder.
The abusive missives despatched through Zendesk’s platform can embody any topic line chosen by the abusers. In my case, the messages variously warned a couple of supposed legislation enforcement investigation involving KrebsOnSecurity.com, or else contained private insults.
Furthermore, the automated messages which might be despatched out from any such abuse all come from buyer domains — not from Zendesk. Within the instance under, replying to any of the junk buyer help responses from The Washington Submit’s Zendesk set up exhibits the reply-to tackle is assist@washpost.com.
One in all dozens of messages despatched to me this week by The Washington Submit.
Notified concerning the mass abuse of their platform, Zendesk mentioned the emails have been ticket creation notifications from buyer accounts that configured their Zendesk occasion to permit anybody to submit help requests — together with nameless customers.
“All these help tickets may be a part of a buyer’s workflow, the place a previous verification shouldn’t be required to permit them to have interaction and make use of the Help capabilities,” mentioned Carolyn Camoens, communications director at Zendesk. “Though we suggest our prospects to allow solely verified customers to submit tickets, some Zendesk prospects choose to make use of an nameless setting to permit for tickets to be created attributable to varied enterprise causes.”
Camoens mentioned requests that may be submitted in an nameless method may make use of an e mail tackle of the submitter’s selection.
“Nevertheless, this methodology will also be used for spam requests to be created on behalf of third occasion e mail addresses,” Camoens mentioned. “If an account has enabled the auto-responder set off primarily based on ticket creation, then this permits for the ticket notification e mail to be despatched from our buyer’s accounts to those third events. The notification may also embody the Topic added by the creator of those tickets.”
Zendesk claims it makes use of price limits to stop a excessive quantity of requests from being created directly, however these limits didn’t cease Zendesk prospects from flooding my inbox with hundreds of messages in just some hours.
“We acknowledge that our programs have been leveraged in opposition to you in a distributed, many-against-one method,” Camoens mentioned. “We’re actively investigating extra preventive measures. We’re additionally advising prospects experiencing any such exercise to comply with our normal safety finest practices and configure an authenticated ticket creation workflow.”
In all the circumstances above, the messaging abuse wouldn’t have been doable if Zendesk prospects validated help request e mail addresses previous to sending responses. Failing to take action might make it simpler for Zendesk shoppers to deal with buyer help requests, but it surely additionally permits ne’er-do-wells to sully the sender’s model in service of disruptive and malicious e mail floods.
