Be on the lookout

I’m hearing more rumors of ESPs seeing customer accounts being compromised, similar to what happened with The Children’s Place.

Experian CheetahMail identified an isolated incident in which someone used a valid client user ID and password to gain access to the client’s email account and transmit an unauthorized and unlawful email. To recipients, the email appeared as a solicitation from an unrelated sender (disguised as Adobe) and directed viewers to an illicit website requesting credit card information. The impact was limited to a single, targeted outbound email.

I have a few suggestions for companies to be able to identify these types of attacks before mail goes out.
1) Set up monitoring to look for large number of uploads in a particular account. Tens of millions of new addresses, even spread over multiple uploads, should raise red flags and trigger manual review of an account.
2) Scan outgoing messages for links mentioning or advertising Adobe (all the spams so far seem to be linking to adobe phish sites).
3) Monitor for unusual send activity. A customer that sends small amounts of mail regularly, but all of a sudden spikes to 10 or 100 times more mail may be compromised.
4) Monitor FBLs for spikes in activity.
5) Monitor bounces for spikes in activity.
Much of this monitoring should trivially slot into the monitoring that you’re already doing as an ESP. You may want to add alerts to go out to relevant people inside your company.

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Another security problem

I had hoped to move away from security blogging this week and focus on some other issues. But today I see that both CAUCE and John Levine are reporting that there is malware spam coming from a Cheetahmail customer.
Looking at what they shared, it may be that Cheetahmail has not been compromised directly. Given mail is only coming from one /29, which belongs to one customer it is possible that only the single customer account has been compromised. If that is the case, then it’s most likely one of the Cheetahmail users at the customer got infected and their Cheetahmail credentials were stolen. The spammer then gained access to the customer’s Cheetahmail account.  It’s even possible that the spammer used the compromised customer account to launch the mail. If this is the case, the spammer looked exactly like the customer, so most normal controls wouldn’t have noticed this was a spammer.
This highlights the multiple vectors these criminals are using to gain access to ESPs and the mailing systems they use. They’re not just trying to compromise the ESPs, but they’re also attempting to compromise customers and access their accounts so that the spammer can steal the ESPs hard won and hard fought sending reputation.
Everyone sending mail should be taking a long, hard look at their security. Just because you’re not an ESP doesn’t mean you aren’t a target or that you can get away with lax security. You are also a target.

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Blocking of ESPs

There’s been quite a bit of discussion on my post about upcoming changes that ESPs will be facing in the future. One thing some people read into the post is the idea that ISPs will be blocking ESPs wholesale without any regard for the quality of the mail from that company.
The idea that ESPs are at risk for blocking simply because they are ESPs has been floating around the industry based on comments by an employee at a spam filter vendor at a recent industry conference.
I talked to the company to get some clarification on what that spam filtering company is doing and hopefully to calm some of the concerns that people have.
First off, and probably most important, is that the spam filtering company in question primarily targets their service to enterprises. Filtering is an important part of this service, but it also handles email archiving, URL filtering and employee monitoring. The target market for the company is very different than the ISP market.
The ISPs are not talking about blocking indiscriminately, they are talking about blocking based on bad behavior.
Secondly, this option was driven by customer request. The customers of the spam filtering appliance were complaining about “legitimate” mail from various ESPs. Despite being reasonable targeted the mail was unrequested by the recipient. While ESPs use FBLs and other sources of complaints to clean complainers off rented or epended lists at ISPs, the option is not available for mail sent to corporations. Enterprises don’t, nor should they have to, create and support FBLs. Nor should employees be expected to unsubscribe from mail they never requested.
This option is the direct result of ESPs allowing customers to send spam.
Thirdly, this option is offered to those customers who ask for it. It is not done automatically for everyone. The option is also configurable down to the end user.
While I haven’t seen the options, nor which ESPs are affected, I expect that the ones on the list are the ones that the filtering vendor receives complaints about. If you are not allowing your customers to send spam, and are stopping them from buying lists or epending, then you probably have not come to the attention of the filtering company and are not on the list of ESPs to block.

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I hate spam

But sometimes it makes me laugh. Yesterday I got a 419 that said, “[…]have been diagonalized with HIV/AIDS which has defiled all forms of medical treatment[…]” Diagonalized? Defiled all forms of treatment?
At least it was entertaining, right?

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