Microsoft IIS DoS, patch install not enough

This blog post is a summary of this week’s Information Security News put together by our Security Incident Response Team (SIRT).

Microsoft announced a bug in the Internet Information Services (IIS) where malicious HTTP/2 packets would consume 100% CPU until restarted. Microsoft have published patches that would allow a MS IIS administrator to mitigate this vulnerability, but would not define any sane default values for the thresholds in question, so installation of the patch itself is not enough. The patch will only enable the options for setting threshold values, it will not set them. Luckily this is only an attack on availability, so you will know when you get attacked, and when the attack is over, a so called Denial of Service (DoS) attack. It will not affect confidentiality of data stored or integrity of the website published.

Read more

Top 5 Security News