Cache Management: Insecure Policy

Insecure caching policies can enable an attacker to conduct content spoofing or information theft attacks.

While content transmitted over an SSL/TLS channel is expected to guarantee confidentiality, administrators must nonetheless ensure that caching of sensitive content is disabled unless absolutely needed. The misconception that secure content caching is disabled by default by user-agents could cause the application to fail the organization's cache policy by leaving the secure content cacheable by browsers. Unsafe specification such as Cache-Control: public would instruct the browser to persistently cache the content on the hard drive. Caching can be prevented by specifying one of the following three directives in the response headers
- Cache-control: private
- Cache-Control: no-cache
- Cache-Control: no-store
SSL provides a secure encrypted channel to transfer information from source to user. The information served over SSL is considered sensitive and trusted to be only available to requestor. However, caching this content on disk in temporary internet files or in intermediate proxy server can compromise that trust by exposing it to everyone who has access to these temporary storage or proxy cache. Content served over SSL must have cache disabled.