Amazon CloudFront Adds Access Logging Capability:
AWS today released access logs for Amazon CloudFront. Access logs are activity records that show you details about every request delivered through Amazon CloudFront. They contain a comprehensive set of information about requests for your content, including the object requested, the date and time of the request, the edge location serving the request, the client IP address, the referrer and the user agent. It’s easy to get started using access logs: you just specify the name of the Amazon S3 bucket you want to use to store the logs when you configure your Amazon CloudFront distribution. There are no fees for using the access logs, beyond normal Amazon S3 charges to write, store and retrieve the logs.
The Amazon Elastic MapReduce team has also built a sample application, CloudFront LogAnalyzer, that will analyze your Amazon CloudFront access logs. This tool lets you use the power of Amazon Elastic MapReduce to quickly turn Access Logs into the answers to the most commonly asked questions about your business. Additionally, several partners have also built solutions that help you analyze these access logs; you can find more information about these in the AWS Solutions Catalog.
Looking at the Developer Guide entry for Access Logs, we see the following sorts of data will be recorded:
The log files use the W3C extended log file format
(for more information, go to http://www.w3.org/TR/WD-logfile.html).
The files contain information for each record in the following order:
Date of the request (in UTC)
Time (when the server finished processing the request; in UTC)
Edge location that served the request
(a variable-length string with a minimum of 3 characters)
Client IP address (no hostname lookups occur)
HTTP access method
DNS name (either the CloudFront distribution name or your CNAME,
whichever the end user specified in the request)
URI stem (e.g., /images/daily-ad.jpg)
HTTP status code (e.g., 200)
An entry might look like this:
#Fields: date time x-edge-location sc-bytes c-ip cs-method cs(Host) cs-uri-stem sc-status
02/01/2009 01:13:11 FRA2 182 10.10.10.10 GET d2819bc28.cloudfront.net /view/my/file.html 200
02/01/2009 01:13:12 LAX1 2390282 18.104.22.168 GET www.singalong.com /soundtrack/happy.mp3 304
I think this is a good start, but I'll leave it to Cloudsecurity.org for expert commentary!
Richard Bejtlich is teaching new classes in Las Vegas in 2009. Regular Las Vegas registration ends 1 July.