Posts Tagged ‘SPAM’

Incident report: Spam filtering overflow filling up disk..

Posted on: December 19th, 2024 by

On Wednesday  2024-12-18 early evening (~19:00 UTC) a spammer attempted to use a Kolab Now account for sending out large amounts of spam. The Kolab Now exit spam filter was sorting out the spam and redirecting it, as it was supposed to do, and none of the spam was sent out. The spammer was however stubborn and kept up the sending, which subsequently was filling up a disk and hence blocking traffic. Due to ongoing maintenance on the monitoring, the full disk was unfortunately not discovered until Thursday morning, when the problem was immediately corrected, and queued mails were again flowing in both directions.

The problem caused a group of users (about 30%) to be unable to receive mail, and sent mail was queued until the space was again freed up and spooling was possible. No mail should have been lost during the incident.

The missing monitoring has been put back into action, and the Kolab Now Engineering team is evaluating changes that will prevent the situation from repeating.

We apologize for any inconvenience that this incident may have caused.

Incident report: One external submission server overwhelmed by spam flood..

Posted on: January 8th, 2024 by

On the 2024-01-07 a spammer made a large flow on one of the external submission servers. The server stopped the spam mails, and saved them to a separate holding queue to make room for other users.

It took a while for the reporting to get to the operations team, but as soon as the issue was known it was swiftly resolved at ~19:00. However, meanwhile the server ran out of space, and some users (who hit that server) would have seen that the send and receive activities failed.

We apologize for the inconvenience that this issue has caused, and will focus on improving the reporting to also cover this specific issue.

A Stricter DMARC Policy, Part II

Posted on: October 9th, 2017 by

Last month, we let you know a stricter DMARC policy was being applied to Kolab Now infrastructure. With a primary aim to increase our reputation and decrease phishing attempts from clearly false senders, we’ve since learned about some secondary effects;

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A Stricter DMARC Policy

Posted on: September 26th, 2017 by

Sometimes, we receive reports that either our general reputation has declined to the point that certain receiving parties will block some of the email sent through our infrastructure, and that bothers us — because it bothers our customers. This usually involves just a limited number of messages, but is annoying nonetheless.

Other times we receive reports of phishing. These usually do not include verbiage that is suitable for repeating in this here blog, as the reports reply to messages do not originate from us, usually refer to external, third party sites but are most importantly also not submitted through our infrastructure. We follow up these occurrences with abuse reports to web server hosting companies, email providers and through other associated channels, but responses are often not thorough and not quick.

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