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denial of service Archives - AWS Managed Services by Anchor

How to explain Hash DoS to your parents by using cats

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We came across this interesting article recently, it’s about how an attacker can perform a denial-of-service attack by feeding perverse input to a system that uses weak hashing algorithms. This is referred to as a Hash DoS, and the specific target mentioned in the article is btrfs. btrfs is a next-gen filesystem that’s expected to replace ext3/4 in Linux. It’s still considered experimental but is quite usable and maturing fast. This article piqued our interest because we’re using btrfs “for reals” here at Anchor. It’s well and good to say that, but the article isn’t very exciting unless you have a background in computer science. How would you explain Hash DoS to your parents, who probably don’t have a CompSci background? This is the internet, so the answer is cats….

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….So you think you have a spam problem?

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Earlier today we started seeing multiple monitoring alerts from our network monitoring station suggesting that two mail servers which we manage were under considerable amounts of system load. This became so bad that email began to be delayed and in some occasions clients attempting to connect via pop and imap were timing out… meaning that mail was unable to be retrieved … This is strange behavior and something that is really only going to occur when the system is under considerable amounts of load. Subsequently, after completing an amount of investigation it appeared that the vast majority of the mail was destined for one specific domain, and addressed to some really suspect emails addresses which were never likely to exist such as: [email protected] – It seemed as though that email…

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