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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ESPs leaking email addresses

Two of my tagged email addresses started getting identical pharma spam over the weekend. It is annoying me because I am now getting spam in a mailbox that was previously spam free. The spam is overwhelming the real traffic and I am having to make some decisions about what to do with the email addresses and their associated accounts with the companies I gave them to.
One thing I did notice, though, is that both companies use iContact as their ESP. A cursory check of my other mailboxes shows that none of my other tagged addresses are mailed through iContact. I don’t think it’s very likely that these two individual, unrelated companies made deals with the same spammers to sell address lists at the same time. It’s much more likely that there was a compromise somewhere and address lists were stolen.
Edit: Checked my other account and, likewise, I’m getting the same spam to a 3rd address serviced by iContact. I’ve sent mail to all 3 companies involved and we’ll see how they react.
And, as I was thinking about this, iContact just laid off a bunch of staff about the same time they announced their partnership with Goodmail. Based on past history with companies in this situation, it seems possible this is a disgruntled former employee. I’ve also seen reports from other people noticing spam to addresses given to iContact customers.

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You've got to be kidding me

Earlier this week I received an email to a work address I retired 4 or 5 years ago. The from and subject lines alone were enough to make me laugh and decide I had to blog about this particular spammer.

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