Evaluation of tamper resistant software system implementations

• US 8,176,560 B2
• Filed: 05/14/2008
• Issued: 05/08/2012
• Est. Priority Date: 05/14/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Jin, Hongxia, Myles, Ginger Marie
• Primary Examiner(s): Lanier, Benjamin
• Assistant Examiner(s): ZECHER, CORDELIA P K
• Application Number:
  US12/152,486
• Publication Number:
  US 20090287679A1
• Time in Patent Office: 1,455 Days
• Field of Search: 726/25
• US Class Current: 726/25
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: G06F 2221/033 Test or assess software

Abstract

According to one embodiment of the present invention, a method for evaluating a software system includes defining a rating of the tamper resistance of a software system and breaking down the rating into a plurality of metrics relevant to the tamper resistance of the software system. A score may then be calculated for each metric and the scores may be combined into a composite score for the rating.

Claims

1. A method comprising:

generating a model of tamper resistance capabilities, the generating comprising;

creating a node in the model for each of a plurality of block of code;

adding directed edges between nodes for each;

node providing integrity verification for another node;

node providing anti-debugging protection to another node; and

node that repairs another node;

adding additionally nodes for each block that contains concealment protection; and

adding a superblock for nodes that provide protection for more than one additional node, the superblock encompassing all of the more than one additional nodes;

defining, by a computer, a rating of the tamper resistance of a software system using data from the model;

breaking down said rating into a plurality of metrics relevant to the tamper resistance of said software system;

calculating, by the computer, a score for each of said metrics; and

combining said scores of said metrics into a composite score for said rating.

2. The method according to claim 1 further comprising:

defining a plurality of sub-ratings of the tamper resistance of said software system;

performing said breaking down and calculating for said plurality of sub-ratings; and

combining a plurality of said composite scores for said plurality of sub-ratings into an overall score for said software system.

3. The method according to claim 2 wherein said combining comprises:

determining a weighted score for each said sub-rating, said weighting based on the relative importance of said sub-rating; and

adding up said weighted scores for each said sub-rating.

4. The method according to claim 2 wherein said combining comprises:

determining a weighted score for each said sub-rating, said weighting based on the relative importance of said sub-rating; and

multiplying said weighted scores for each said sub-rating.

5. The method according to claim 1 wherein said rating is a rating of how much of said software system is covered by a protection mechanism.

6. The method according to claim 1 wherein said rating is a rating of the complexity of said software system.

7. The method according to claim 1 wherein said rating is a rating of auxiliary protection incorporated into said software system.

8. The method according to claim 1 wherein said combining comprises:

determining a weighted score for each said metric, said weighting based on the relative importance of said metric; and

combining said weighted scores for each metric.

9. The method according to claim 1 wherein the model is a graphical model.

10. The method according to claim 1 wherein said constructing comprises constructing a graphical representation of the relationship between functions of said software system.

11. A method comprising:

generating a model of tamper resistance capabilities, the generating comprising;

creating a node in the model for each of a plurality of block of code;

adding directed edges between nodes for each;

node providing integrity verification for another node;

node providing anti-debugging protection to another node; and

node that repairs another node;

adding additionally nodes for each block that contains concealment protection; and

adding a superblock for nodes that provide protection for more than one additional node, the superblock encompassing all of the more than one additional nodes;

defining, by a computer, a rating and a plurality of sub-ratings of the tamper resistance of a software system, using data from the model;

breaking down said plurality of sub-ratings into a plurality of metrics relevant to the tamper resistance of said software system;

calculating, by the computer, a score for each metric;

combining, by the computer, said scores of said metrics into composite scores for said sub-ratings; and

combining, by the computer, said composite scores for said sub-ratings into an overall score for said rating.

12. The method according to claim 11 wherein said model comprises a graphical model.

13. The method according to claim 11 wherein said constructing comprises constructing a graphical representation of the relationship between functions of said software system.

14. The method according to claim 11 wherein said combining comprises:

determining a weighted score for each said metric, said weighting based on the relative importance of said metric; and

combining said weighted scores for each metric.

15. A method comprising:

generating a model of tamper resistance capabilities, the generating comprising;

creating a node in the model for each of a plurality of block of code;

adding directed edges between nodes for each;

node providing integrity verification for another node;

node providing anti-debugging protection to another node; and

node that repairs another node;

adding additionally nodes for each block that contains concealment protection; and

adding a superblock for nodes that provide protection for more than one additional node, the superblock encompassing all of the more than one additional nodes;

defining, by a computer, a rating of the tamper resistance of at least two software systems using data from the model;

decomposing said rating into at least one sub-rating that is a subset of said rating;

breaking down said sub-rating into a plurality of metrics relevant to the tamper resistance of said at least two software systems;

calculating, by the computer, a score for each metric;

combining, by the computer, said scores of said metrics into a composite score for said sub-rating and combining said scores of said sub-ratings into a composite score for the said rating for each of said at least two software systems; and

comparing, by the computer, said ratings of different ones of said at least two software systems to determine which software system has the highest tamper resistance.

16. The method according to claim 15 wherein said sub-rating is a rating of how much of said software system is covered by a protection mechanism.

17. The method according to claim 15 wherein said sub-rating is a rating of the complexity of said software system.

18. The method according to claim 15 wherein said sub-rating is a rating of auxiliary protection incorporated into said software system.

19. A method of providing a rating of a software system comprising:

receiving, by a computer, a software system from an entity;

generating a model of tamper resistance capabilities, responsive to the receiving, the generating comprising;

creating a node in the model for each of a plurality of block of code;

adding directed edges between nodes for each;

node providing integrity verification for another node;

node providing anti-debugging protection to another node; and

node that repairs another node;

adding additionally nodes for each block that contains concealment protection; and

adding a superblock for nodes that provide protection for more than one additional node, the superblock encompassing all of the more than one additional nodes;

defining a rating of the tamper resistance of said software system using data from the model;

decomposing said rating into at least one sub-rating that is a subset of said rating;

breaking down said sub-rating into a plurality of metrics relevant to the tamper resistance of said software system;

calculating, by the computer, a score for each metric using data from the model;

combining, by the computer, said scores of said metrics into a composite score for said sub-rating and combining said scores of said sub-ratings into a composite score for said rating; and

providing a security rating for said software system to said entity.

20. The method according to claim 19 wherein said combining comprises:

determining a weighted score for each said metric, said weighting based on the relative importance of said metric; and

combining said weighted scores for each metric.

21. The method according to claim 19 wherein said model is a graphical model.

22. The method according to claim 19 wherein said constructing comprises constructing a graphical representation of the relationship between functions of said software system.

23. A computer program product for rating the tamper resistance of a software system, the computer program product comprising:

a non-transitory computer readable storage medium having computer usable program code embodied therewith, the computer usable program code comprising;

computer usable program code configured to;

generate a model of tamper resistance capabilities, the generating comprising;

creating a node in the model for each of a plurality of block of code;

adding directed edges between nodes for each;

node providing integrity verification for another node;

node providing anti-debugging protection to another node; and

node that repairs another node;

adding additionally nodes for each block that contains concealment protection; and

adding a superblock for nodes that provide protection for more than one additional node, the superblock encompassing all of the more than one additional nodes;

define a rating of the tamper resistance of a software system using data from the model;

decompose said rating into at least one sub-rating that is a subset of said rating;

break down said sub-rating into a plurality of metrics relevant to the tamper resistance of said software system;

calculate a score for each metric using data from the model; and

combine said scores of said metrics into a composite score for said rating.

24. The computer program product according to claim 23 wherein said model is a graphical model.

25. The method according to claim 23 wherein said constructing comprises constructing a graphical representation of the relationship between functions of said software system.