Simon Willison’s Weblog

Entries tagged security in Feb

Filters: Type: entry × Month: Feb × security ×


What are the best practices to avoid XSS and SQL Injections attacks (platform agnostic)?

Input validation is, in my opinion, a red herring. Sure—if you ask the user for an integer or date you should make sure they entered one before attempting to save it anywhere or use it for processing, but injection attacks often involve text fields (e.g. names, or comments posted on Quora) and validating those on input is a recipe for banning “Tim O’Reilly” from ever creating a proper profile on your site!

[... 316 words]

Bizex

I’m going to try not to turn this in to a blog about Windows security exploits but this one is genuinely interesting in that it actively tries to steal financial information and important passwords. Bizex spreads itself by spamming messages over ICQ advising the recipient to visit a specific URL. When they visit it, Internet Explorer exploits are used to download and execute the main payload which then infects their ICQ program and uses it to message their contacts. The worm also scans their hard drive for information relating to a number of well known financial services which it then uploads to a server via FTP, and it apparently snoops on their browser for any passwords travelling over HTTPS connections as well.

[... 216 words]

Novel security measures

An article on SecurityFocus led me to this site about Port Knocking. Port Knocking is an interesting security technique in which a box sits online with no ports open to connections and awaits a specific sequence of connection attempts. A user wishing to connect to the box must first attempt to initiate connections to ports in a specific, secret order. Once they do, the box starts up the required service (such as an SSH daemon) on a designated port and allows the user to connect properly.

[... 145 words]

“I’m Brian and so’s my wife”

I’m subscribed to a whole bunch of mailing lists, mostly as a lurker as I have a hard enough time just keeping up with some of them. One of those lists is Bugtraq, which is pretty much required reading for anyone with sysadmin responsibilities for a server connected to the public internet. Bugtraq is the central hub of the “public disclosure” security community and is actually surprisingly low traffic with only twenty or so messages a day. It’s fascinating to watch the latest exploits for all manner of popular software packages tick by on an hourly basis.

[... 285 words]

Hashing client-side data

Via Scott, a clever PHP technique for ensuring data sent to the browser as a cookie or hidden form variable isn’t tampered with by the user:

[... 248 words]