Improper Enforcement of Behavioral Workflow

Opis

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:

- Steps are performed in the expected order.

- Required steps are not omitted.

- Steps are not interrupted.

- Steps are performed in a timely fashion.

Skutki

• Other

  Alter Execution Logic

  An attacker could cause the product to skip critical steps or perform them in the wrong order, bypassing its intended business logic. This can sometimes have security implications.

Przykłady podatności

• CVE-2011-0348 Bypass of access/billing restrictions by sending traffic to an unrestricted destination before sending to a restricted destination.
• CVE-2007-3012 Attacker can access portions of a restricted page by canceling out of a dialog.
• CVE-2009-5056 Ticket-tracking system does not enforce a permission setting.
• CVE-2004-2164 Shopping cart does not close a database connection when user restores a previous order, leading to connection exhaustion.
• CVE-2003-0777 Chain: product does not properly handle dropped connections, leading to missing NULL terminator (CWE-170) and segmentation fault.
• CVE-2005-3327 Chain: Authentication bypass by skipping the first startup step as required by the protocol.
• CVE-2004-0829 Chain: File server crashes when sent a "find next" request without an initial "find first."
• CVE-2010-2620 FTP server allows remote attackers to bypass authentication by sending (1) LIST, (2) RETR, (3) STOR, or other commands without performing the required login steps first.
• CVE-2005-3296 FTP server allows remote attackers to list arbitrary directories as root by running the LIST command before logging in.

Słabość nadrzędna

• CWE-691 Insufficient Control Flow Management

Kiedy powstaje

• Implementation — REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Dotyczy

Not Language-Specific

Uwagi

This weakness is typically associated with business logic flaws, except when it produces resultant weaknesses.

The classification of business logic flaws has been under-studied, although exploitation of business flaws frequently happens in real-world systems, and many applied vulnerability researchers investigate them. The greatest focus is in web applications. There is debate within the community about whether these problems represent particularly new concepts, or if they are variations of well-known principles.

Many business logic flaws appear to be oriented toward business processes, application flows, and sequences of behaviors, which are not as well-represented in CWE as weaknesses related to input validation, memory management, etc.

Źródła

1. Business Logic Flaws and Yahoo Games — Jeremiah Grossman, 2006
2. Seven Business Logic Flaws That Put Your Website At Risk — Jeremiah Grossman, 2007
3. Business Logic Flaws — WhiteHat Security
4. Insufficient Process Validation — WASC
5. Defying Logic: Theory, Design, and Implementation of Complex Systems for Testing Application Logic — Rafal Los, Prajakta Jagdale, 2011
6. Real-Life Example of a 'Business Logic Defect' (Screen Shots!) — Rafal Los, 2011
7. Toward Automated Detection of Logic Vulnerabilities in Web Applications — Viktoria Felmetsger, Ludovico Cavedon, Christopher Kruegel, Giovanni Vigna, USENIX Security Symposium 2010, 2010
8. Designing a Framework Method for Secure Business Application Logic Integrity in e-Commerce Systems — Faisal Nabi, pages 29 - 41, International Journal of Network Security, Vol.12, No.1, 2011