Automated penetration analysis system and method

• US 5,485,409 A
• Filed: 04/30/1992
• Issued: 01/16/1996
• Est. Priority Date: 04/30/1992
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation, University of Maryland
• Original Assignee: International Business Machines Corporation
• Inventors: Gligor, Virgil D., Gupta, Sarbari
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): Stamber, Eric W.
• Application Number:
  US07/875,945
• Time in Patent Office: 1,356 Days
• Field of Search: 364/580, 364/570, 364/918.7, 364/949.81, 364/286.4, 364/286.5, 364/286.6, 364/419, 395/50, 395/51, 395/61, 395/911, 395/912, 395/913, 395/914, 395/915, 395/916, 395/917, 395/918, 395/725, 340/825.31, 340/825.34, 380/4
• US Class Current: 726/25
• CPC Class Codes: G06F 21/577 Assessing vulnerabilities and evaluating computer system security

Abstract

The present invention provides a penetration-analysis method, which (1) provides a systematic approach to penetration analysis, (2) enables the verification of penetration-resistance properties, and (3) is amenable to automation. An Automated Penetration Analysis (APA) tool is provided, to support the penetration analysis method. The penetration-analysis system and method is based on a theory of penetration-resistant computer systems, a model of penetration analysis, and a unified representation of penetration patterns. The theory consists of the Hypothesis of Penetration-Resistant Systems and a set of design properties that characterize resistance to penetration. The penetration-analysis model defines a set of states, a state-invariant for penetration resistance, and a set of rules that can be applied for analyzing the penetration vulnerability of a system. An interpretation of the Hypothesis of Penetration-Resistant Systems within a given system provides the Hypothesis of Penetration Patterns, which enables the present invention to define a unified representation for a large set of penetration instances as missing check patterns.

Claims

1. A method for preventing users of a computer system from exploiting system flaws to gain illegal or unintended access to system variables, objects and/or operations, comprising the steps of:

(1) generating a set of interpretation constants by applying a set of penetration-resistant properties to a given system, wherein said set of interpretation constants represent a database of required conditions, parameter validations and privilege checks that are associated with access to each abstract cell and critical function in said given system, wherein said given system has previously been determined to be penetration-resistant;

(2) generating an integrated flow path within said given system which records information regarding flows and condition checks that would be encountered along a given integrated flow path to an alter operation or a view operation on a particular abstract cell or an invoke operation on an internal system function;

(3) applying, in response to said alter operation, said view operation, or said invoke operation, a set of model rules to said given integrated flow path to determine whether said given integrated flow path conforms to said penetration-resistant properties, wherein said model rules are based on said interpretation constants; and

(4) allowing said alter operation, said view operation, or said invoke operation to proceed if said given integrated flow path was in conformity with said penetration-resistant properties.

2. The method of claim 1, wherein said interpretation constants include an alter set, a view set, a critical function set, and an entry point set.

3. The method of claim 1, wherein said penetration-resistant properties include (a) system isolation, (b) system noncircumventability, (c) consistency of system global variables, (d) timing consistency of system condition checks, and (e) elimination of undesirable user and system dependencies.

4. The method of claim 1, wherein said integrated flow path is modified if all conditions of an alter model rule are met, said alter model rule comprising the steps of:

(a) determining whether said given integrated flow path includes all required entry point parameter validation checks;

(b) determining whether said given integrated flow path includes all required conditions that need to be checked to alter a given abstract cell; and

(c) determining whether all of said required conditions are checked and said given abstract cell is altered in a sequence that does not invoke a sleep function;

wherein said alter model rule is applied when said alter operation attempts to alter said given abstract cell through a system entry point along said given integrated flow path.

5. The method of claim 1, wherein said integrated flow path as modified if all conditions of a view model rule are met, said view model rule comprising the steps of:

(a) determining whether said given integrated flow path includes all required entry point parameter validation checks;

(b) determining whether said given integrated flow path includes all required conditions that need to be checked to view a given abstract cell; and

(c) determining whether all of said required conditions are checked and said given abstract cell is viewed in a sequence that does not invoke a sleep function;

wherein said view model rule is applied when said view operation attempts to view said given abstract cell through a system entry point along said given integrated flow path.

6. The method of claim 1, wherein said integrated flow path is modified if all conditions of an invoke model rule are met, said invoke model rule comprising the steps of:

(a) determining whether said given integrated flow path includes all required entry point parameter validation checks;

(b) determining whether said given integrated flow path includes all required conditions that need to be checked before a critical function can be legally invoked; and

(c) determining whether all of said required conditions are checked and said critical function is invoked in a sequence that does not invoke a sleep function;

wherein said invoke model rule is applied when said invoke operation attempts to invoke said critical function through a system entry point along said given integrated flow path.