CWE-841: Improper Enforcement of Behavioral Workflow

Description

The product supports a session in which more than one behavior must be performed by an actor, but it does not properly ensure that the actor performs the behaviors in the required sequence.

By performing actions in an unexpected order, or by omitting steps, an attacker could manipulate the business logic of the product or cause it to enter an invalid state. In some cases, this can also expose resultant weaknesses. For example, a file-sharing protocol might require that an actor perform separate steps to provide a username, then a password, before being able to transfer files. If the file-sharing server accepts a password command followed by a transfer command, without any username being provided, the product might still perform the transfer. Note that this is different than CWE-696, which focuses on when the product performs actions in the wrong sequence; this entry is closely related, but it is focused on ensuring that the actor performs actions in the correct sequence. Workflow-related behaviors include:

Potential Impact

Demonstrative Examples

def dispatchCommand(command, user, args):
                        if command == 'Login':loginUser(args)return
                           
                           
                           # user has requested a file
                           if command == 'Retrieve_file':
			   
			   if authenticated(user) and ownsFile(user,args):
			   
			   sendFile(args)return
			   
                           if command == 'List_files':listFiles(args)return
                           
                           ...

def dispatchCommand(command, user, args):
                        
                           
                           ...
                           if command == 'List_files':if authenticated(user) and ownsDirectory(user,args):listFiles(args)return
                           
                           
                           ...

Detection Methods

• Automated Static Analysis — Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then sea

Real-World CVE Examples

Related Weaknesses

Taxonomy Mappings

• WASC: 40 — Insufficient Process Validation