US 9,805,188 B2Granted

Control flow integrity system and method

AssigneeRunsafe Security, Inc.

InventorsAndrew Michael Wesie, Brian Sejoon Pak

Life of this patent

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Abstract

An improved CFI system and method is described that provides security from attacks to hijack computer software. The improved CFI system and method inserts two tags to execute label identification. The first tag is positioned before any instruction that would result in an indirect control flow transfer and requires the program to execute a check. The second tag is located before the first line of any legitimate transfer destination and when discovered by the tag check allows a program to carry out the indirect transfer. This tag orientation does not prevent transfers to targets other than the origin instruction's specific intended destination but limits transfers to destinations that begin with the proper label dedication. Although, an incorrect address may be called, that will be within the software program's assortment of legitimate indirect transfer targets. Attempts to exploit or reroute indirect transfers outside of the established control flow are eliminated.

Claims21

Dependent claims

A two-tiered computer-based security method for protecting binary code and associated libraries from access by unauthorized users during loading of the binary code and associated libraries and launching the binary code and associated libraries, comprising the steps of:

(A) at a first tier of the method, an operating system loading a launcher program for overseeing the launching of the binary code and associated binary code libraries to be protected, the launcher program being loaded by,
(1) the operating system requesting a computer registry to load the binary code and associated libraries to be protected;
(2) the computer registry redirecting the loading of the launcher program and associated libraries in place of the binary code and associated libraries to be protected,
(3) the operating system loading the launcher program and associated libraries, and
(4) the operating system running the launcher program and associated libraries for input to and controlling a second tier of the method, and
(B) at the second tier of the method, the operating system running the launcher program to oversee modification of the binary code and associated libraries to be protected by,
(1) the operating system loading the binary code and associated libraries,
(2) the operating system under the control of the launcher program rewriting the binary code and associated binary code libraries, with the rewriting of the binary code and associated libraries being such that the operating functionality of the binary code and associated libraries remain substantially the same and with the binary code and associated libraries being located at a new location in system memory as controlled by the launcher program,
(3) the operating system under the control of the launcher program generating and storing a hash table which contains a mapping to redirect calls and returns for indirect control flow transfers from the binary code and associated libraries to the rewritten binary code and rewritten associated binary code libraries, with knowledge of the redirection being controlled by the launcher program, and
(4) the operating system running the protected binary code and associated libraries in the form of the rewritten binary code and rewritten associated libraries.

7 more elements

A system for protecting binary code and associated libraries from access by unauthorized users during loading of the binary code and associated libraries and launching the binary code and associated libraries, comprising one or more computer processors coupled to a memory, configured to:

(A) load a launcher program for overseeing the launching of the binary code and associated binary code libraries to be protected, the launcher program being configured to be loaded by,
(1) requesting a computer registry to load the binary code and associated libraries to be protected;
(2) redirecting, via the computer registry, the loading of the launcher program and associated libraries in place of the binary code and associated libraries to be protected,
(3) loading the launcher program and associated libraries, and
(4) running the launcher program and associated libraries for input to and controlling the binary code and associated libraries, and
(B) run the launcher program to oversee modification of the binary code and associated libraries to be protected by,
(1) loading the binary code and associated libraries,
(2) under the control of the launcher program, rewriting the binary code and associated binary code libraries, with the rewriting of the binary code and associated libraries being such that the operating functionality of the binary code and associated libraries remain substantially the same and with the binary code and associated libraries being located at a new location in system memory as controlled by the launcher program,
(3) under the control of the launcher program, generating and storing a hash table which contains a mapping to redirect calls and returns for indirect control flow transfers from the binary code and associated libraries to the rewritten binary code and rewritten associated binary code libraries, with knowledge of the redirection being controlled by the launcher program, and
(4) running the protected binary code and associated libraries in the form of the rewritten binary code and rewritten associated libraries.

7 more elements

An article of manufacture for protecting binary code and associated libraries from access by unauthorized users during loading of the binary code and associated libraries and launching the binary code and associated libraries, the article of manufacture comprising:

at least one non-transitory processor readable hardware storage medium;
and
instructions stored on the at least one medium;
wherein the instructions are configured to be readable from the at least one medium by at least one processor and thereby cause the at least one processor to operate so as to:
(A) load a launcher program for overseeing the launching of the binary code and associated binary code libraries to be protected, the launcher program being loaded by,
(1) requesting a computer registry to load the binary code and associated libraries to be protected;
(2) redirecting, by the computer registry, the loading of the launcher program and associated libraries in place of the binary code and associated libraries to be protected,
(3) loading the launcher program and associated libraries, and
(4) running the launcher program and associated libraries for input to and controlling the binary code and associated libraries, and
(B) run the launcher program to oversee modification of the binary code and associated libraries to be protected by,
(1) loading the binary code and associated libraries,
(2) under the control of the launcher program, rewriting the binary code and associated binary code libraries, with the rewriting of the binary code and associated libraries being such that the operating functionality of the binary code and associated libraries remain substantially the same and with the binary code and associated libraries being located at a new location in system memory as controlled by the launcher program,
(3) under the control of the launcher program, generating and storing a hash table which contains a mapping to redirect calls and returns for indirect control flow transfers from the binary code and associated libraries to the rewritten binary code and rewritten associated binary code libraries, with knowledge of the redirection being controlled by the launcher program, and
(4) run the protected binary code and associated libraries in the form of the rewritten binary code and rewritten associated libraries.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/538,643Filed 11 Nov 2014 · us provisional application
Priority: 12 Nov 2013
Published: US 2015/0135313 A114 May 2015
Granted: 31 Oct 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G06F 21/51
Monitoring users, programs or devices to maintain the integrity of platforms, e.g. of processors, firmware or operating systems: at application…
G06F 8/53
Transformation of program code: decompilation; Disassembly
G06F 9/445
Arrangements for executing specific programs: program loading or initiating
G06F 9/44521
Program loading or initiating: dynamic linking or loading; Link editing at or after load time, e.g. Java class loading