Why the hack?

Why attacking and hacking – proof of concept – causes service interruption – utilize compromised systems to attack other targets – steal compute power – build zombie network – ransome – attention seeking – personal reasons How does it happen – Webhack exploiting vulnerable apps or scripts – SQL injection – Overflow boundaries – Brutish password hack – Social hacking – Affected by compromised neighbors particularly in muti-tenant environments –…

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Meltdown and Spectre CVE-2017-5715

Numerous posts and announcements have been made available in past 48 hours[1]. I don’t want to embarrass myself trying to describe what they’re about. Here I want to measure the performance penalty for the kernel patch. Kernel update has been made available on CentOS 7 (3.10.0-693.11.6.el7), roughly 12 hours behind Redhat. Here is a quick test of mysql sysbench on a small instance on aliyun, AWS, and Azure. No impact…

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Using list and lookup in terraform HCL

Terraform delivers consistent build and save a lot of time from clicking and scrolling. But when the resources, in this case ec2 resources are slightly different, it may be necessary to create a tf config for every instance. That defeats the purpose of automation. By storing the differences in a list and use the lookup function to extract the values, I’m able to write the following tf config with little…

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aliyun

Switched to aliyun international today. It’s incredibly fast compared to DigitalOcean in the same region. Monthly charge is reduced by almost 50% [1] Blazing fast Compared to what I previous used, network performance exceeds my expectation. My DO vm was in the same region. Very often I had to wait 3-10 seconds for my blog to load. After moving to aliyun, the site loads in under a second. Sorry but…

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Writing a wordpress plugin to filter comments

I’m completely new to wordpress plugin development. I want to write a plugin to delete comments I don’t want based on a keyword list. Update: WordPress already comes with this feature under Comment Moderation The code The code isn’t complex. It first use the preprocess_comment hook to check the comment content. If it contains hyperlinks, a 404 error will be returned and the comment will not be inserted into database.…

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