[VELOCITY-931] SecureUberspector should block methods on ClassLoader and subclasses

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.3
• Assignee: William Glass-Husain
• Reporter: William Glass-Husain
• Created: 17/Jul/20 04:31
• Updated: 23/Mar/21 03:42
• Resolved: 25/Feb/21 22:34

Description

Currently, SecureUberspector matches classes stored with property "introspector.restrict.classes", which includes ClassLoader.   It then matches exact class names and blocks all methods from being called on that class.

However, in most cases it's actually a subclass of ClassLoader that's available in the context, which under normal circumstances would not be blocked.

My proposal – treat this as a special case.  (Remove it from the configuration).  If the class being inspected is assignable from ClassLoader, then block it.   

You could make an argument that all the SecureUberspector should check if the class isAssignable from all configured classes, but I am concerned about possible performance penalties.  I'd argue that we should hard code checks for a few special internal classes but force the user to configure other specific classes themselves.

 

Issue Links

• is cloned by: VELOCITY-941 1.7.x backport for SecureUberspector should block methods on ClassLoader and subclasses