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Nginx: Caching Proxy
May 6th
Recently I started to tackle a load problem on one of my personal sites, the issue was that of a poorly written but exceedingly MySQL heavy application and the load it would induce on the SQL server when 400-500 people were hammering the site at once. Further compounding this was Apache’s horrible ability to gracefully handle excessive requests on object heavy pages (i.e: images). This left me with a site that was almost unusable during peak hours — or worse — would crash the MySQL server and take Apache with it by frenzied F5ing from users.
I went through all the More >
IRSYNC & Limiting Passwordless SSH Keys
May 4th
Anyone who has ever used SSH key-pairs to access more than a couple of servers (or hundreds in my case), will tell you they are an invaluable convenience. It is a natural progression and very common usage that SSH key-pairs are coupled with other common tasks or tools, where having a pass phrase attached to the key would be counter-intuitive to the task automation. So, what do we do despite our better judgment? We create key-pairs with absolutely no pass phrase. The implications are abundantly obvious, if the private key ever gets lost or stolen, any accounts that have the More >
Upgrade CentOS 4.8 to 5.3
Oct 20th
Traditionally, the dist upgrade path that many were familiar with from the RH8/9->Fedora or similarly Fedora dist upgrades, have applied more or less to RHEL/CentOS but with the release of 4.5 and early releases of 5.0 the actual dist upgrade path was messy or nearly impossible. The early versions of 5.0 (up to 5.2) had excessive dependency issues with versions later than 4.4 for straight dist upgrades that would often result in a box blowing up on you or forcing a messy downgrade attempt of 4.5+ to 4.4 to try get things to dist upgrade. With more recent release updates More >
Snorting the Web Farm
Jun 10th
Here are some rules for you snort freaks to chew on that I have found useful in web heavy environments.
alert tcp $HTTP_SERVERS $HTTP_PORTS -> any any (msg:"ET ATTACK RESPONSE x2300 phpshell detected"; content:"Locus7Shell"; nocase; classtype:web-application-activity; reference:url,www.rfxn.com; sid:300010; rev:1;) alert tcp $HTTP_SERVERS $HTTP_PORTS -> any any (msg:"ET ATTACK RESPONSE RFI Scanner detected"; content:"RFI Scanner"; classtype:web-application-activity; reference:url,www.rfxn.com; sid:300020; rev:2;) alert tcp $HTTP_SERVERS $HTTP_PORTS -> any any (msg:"ET ATTACK RESPONSE lila.jpg phpshell detected"; content:"CMD PHP"; classtype:web-application-activity; reference:url,www.rfxn.com; sid:300030; rev:2;) alert tcp $HTTP_SERVERS $HTTP_PORTS -> any any (msg:"ET ATTACK RESPONSE ALBANIA id.php detected"; content:"UNITED ALBANIANS aka ALBOSS PARADISE"; classtype:web-application-activity; reference:url,www.rfxn.com; sid:300040; rev:2;) alert tcp More >
BOGON Filtering, Update It
Apr 17th
One of the features used by APF to prevent address spoofing is that it filters reserved IP address space, also known as BOGON filtering. This is an otherwise very reliable method to keep out random unallocated spoofed addresses from injecting traffic towards your server, assuming of course the list is updated regularly.
We decided a few months ago that we would disable by default all remote features in APF, including the auto updating of the reserved networks file (BOGON filter list), however this was done with one ill-fated consequence… That if you do not turn on the update feature yourself you More >
