KR20080043204A - File format analysis system and method for unknown file format to use software security testing - Google Patents

Abstract

A system and a method for analyzing an unknown file format to test security of software are provided to reduce error processing owing to format mismatch by extracting/converting a field position and a data type of the unknown file format into a value for a fault operation to increase code coverage for the unknown file format. A file scanner(104) parses function parameters of a loaded file by monitoring a target program(103) loading an unknown file(101) to a memory. A file analyzer(106) extracts a field position and a data type of an unknown file format by receiving parsing information from the file scanner. The file scanner is a debugger for tracing a function when the unknown file is loaded on the memory, and the file analyzer extracts the field position and the data type of the unknown file format by comparing the function parameter with the loaded file.

Description

FILE FORMAT ANALYSIS SYSTEM AND METHOD FOR UNKNOWN FILE FORMAT TO USE SOFTWARE SECURITY TESTING}

1 is a block diagram of a system for automatically analyzing field positions and data types for unknown file formats of the present invention;

2 is a structure of a stack for classifying three types of data delivered as function parameters,

3 is a block diagram illustrating a mechanism for extracting a data field of a file through a function parameter.

<Explanation of symbols for the main parts of the drawings>

104: File Scanner 106: File Analyzer

The present invention relates to an unknown file format analysis system and method for performing software security testing, and more particularly, to extract field positions for unknown file formats when using fault injection techniques during software testing. An unknown file format analysis system and method for performing software security testing that improves code coverage.

Here, code coverage refers to how much of the compiled code is tested.

Due to the rapid development of technology in the IT field, the technology of the software must be developed accordingly. As such, software has emerged as an important element in the computer and communication fields. For this reason, the reliability of the software is directly related to the reliability of the system operation, and quality control for this is required. Software quality control is a representative example, and software testing techniques are used the most.

Recently, as the demand for reliability increases variously due to the nature of the software, the testing cost and time increase much. Because of this, automation must be done to reduce software testing time and costs. Test automation is already underway, and as an example, it automatically generates test scripts, test data, and test drivers based on source code analysis results, greatly reducing test time and costs by greatly improving the initial testing process. The solution is being presented. As such, overall automation for software testing, from test case creation to test execution and analysis, is being realized.

On the other hand, the defect insertion method using a file, which is one of the software testing techniques, often inserts a defect without considering the file format, so it is often treated as an error by its own error handling mechanism in the system. There was a problem that the ratio that induces is not high. And even if the file format is open, much time is required to use the defect insertion method in consideration of the file format.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a field position of an unknown file format in order to increase code coverage of an unknown file format in a software defect detection method using a file. An object of the present invention is to provide an unknown file format analysis system and method for performing software security testing to reduce error handling due to format mismatch by extracting a data type and changing the value to a value for a defect operation.

An unknown file format analysis system for performing the software security testing of the present invention for achieving the above object, a file scanner for monitoring a program that loads an unknown file into the memory to parse the function parameters of the loaded file And a file analyzer that receives the parsed information from the file scanner and extracts a field position and a data type of the unknown file format.

In this case, the file scanner refers to a debugger that tracks a function when an unknown file is loaded into a memory, and the file analyzer compares the function parameter and the loaded file to extract a field position and a data type of a file format. Means.

On the other hand, unknown file format analysis method for performing the software security testing of the present invention, (a) monitoring the operation of the program to load the unknown file into the memory in the file scanner, (b) the loaded Parsing a function parameter of a file, (c) receiving the parsed information from a file analyzer to extract field positions and data types of unknown file formats, and (d) extracting the field positions and And changing the value to a value for a defect operation in consideration of the data type.

In this case, in the step (b), parsing may be performed according to a file format by extracting and dividing into a number type and a string type corresponding to the use of the file data in the stack.

In addition, the step (c) includes performing a parameter check when calling a function, performing a case-by-case analysis corresponding to the number of parameters of the function, and storing the case-by-case analysis result. It can be made, including.

Hereinafter, an unknown file format analysis system and method for performing software security testing of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of a system for automatically analyzing field positions and data types for unknown file formats of the present invention.

The system for carrying out the present invention is composed of a file scanner (104) and a file analyzer (106).

The file scanner refers to a module for monitoring the operation of a program that loads an unknown file format, and the file analyzer refers to a module for analyzing field positions and data types of the file format using information monitored by the file scanner. In other words, the file scanner functions as a debugger that can track functions when the target file is loaded into memory, and the file analyzer analyzes the extracted data to extract field positions and data types from data in unknown file formats. Do this.

As such, the present invention performs field position and data type analysis on unknown file formats through a system consisting of a file scanner and a file analyzer.

An operation of an unknown file format analysis system for performing software security testing of the present invention configured as described above will be described schematically.

As shown in FIG. 1, when a file 101 of an unknown file format is loaded into a memory, the target program 103 calls various functions to use the data of the file 102. The file scanner debugs the program that is loading the file. The file scanner monitors the parameters of the functions called in the process of loading the target file and transmits the relevant information to the file analyzer 106 in the form of parsing data 105. Accordingly, the file analyzer outputs information 107 on the field position and data type of the unknown file format using the information received from the file scanner.

2 is a structure of a stack for classifying three types of data delivered as function parameters.

As shown in FIG. 2, the file data is used in the stack for parsing according to the file format after the data of the file is loaded into the memory.

Here, data types to be extracted are classified into two types as follows.

Number type: 2 bytes or 4 bytes, used explicitly in software.

-String type: All types other than male type are considered to be string type. Although not string type, long data string is also considered to be string type.

As such, when the data type is divided into two, a number and a string, the function parameter values can be defined in the following three cases.

(CASE 1) Address 201 pointing to some data in a file in memory. The pointing data can be a string or a data structure. Since these values do not know the file format, they do not know what they represent. Therefore, it is necessary to continuously observe how it is parsed later. In the case of a string, the address value is often used as it is for string related functions. In such cases, the string is considered a string. In the case of data structures, strings may be decomposed in subsequent function calls and broken up into multiple numbers or addresses that point to some data. Therefore, since it is not known whether it is a string or a data structure, it constantly monitors the value and analyzes what is used.

-(CASE 2) Explicitly used as a number (202): A case in which two or four bytes of data in a file are directly used. These values are often used explicitly as numbers in the file format, and these values determine the location within the file and the number of bytes used, and later perform fault-related fault operations when performing fault insertion. To perform. This value can be used as an offset indicating a location in the file, but this value is also explicitly used as a number.

(CASE 3) Software self-generated data 203: The values of the corresponding parameters are values generated by internal needs when the software loads the file. These values can be used as numbers or as addresses that point to some data, but are not necessary when determining field locations in a file and are therefore ignored in field analysis for unknown file formats of the present invention.

3 is a block diagram illustrating a mechanism for extracting a data field of a file through a function parameter.

Referring to FIG. 3, the file analyzer 106 illustrates a process of extracting the location and data type of a field based on the three cases of FIG. 2.

When the normal file is loaded in response to the execution instruction (S1), the parameter check is performed when the function is called (S2).

Parameter count represents the number of parameters of the function (S3), and analyzes the cases of CASE1, CASE2, and CASE3 by the number of parameters.

In case of CASE3, the value is ignored because it is not used to locate the field in the file data (S4).

In case of CASE2, it is explicitly used as a number, so the location of the file containing the parameter value and the length of the field are stored as 2 or 4 bytes. In this case, since the location of the required field in the file data has been determined, the tracking is no longer performed (S5 to S6).

In case of CASE1, it is impossible to know whether the data pointed to is a string or a data structure. However, we can see what this string is going to parse as the function is called later. Therefore, for now, the data type is unknown, but for later monitoring, it stores the location and range of the data area stored in memory and a pointer to this area. These values are used to extract the data type in the subsequent function call (S7 ~ S8).

This process is performed repeatedly (S3 to S8) corresponding to the number of parameters (S9).

Although the present invention has been described in more detail with reference to some embodiments, the present invention is not necessarily limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention.

As described above, an unknown file format analysis system and method for performing software security testing according to the present invention can be achieved by reducing the process of error processing performed due to format mismatch in software testing by matching the specification of a given file format if possible. A limited number of fault-generating files can be used to efficiently derive as many software defects as possible. As such, the present invention has an advantage of increasing code coverage when using a defect insertion technique by extracting field position and data type information for a file format for an unknown file format.

Claims (14)

A file scanner that monitors a program that loads a file that is unknown to memory and parses function parameters of the loaded file; And File analyzer which receives the parsed information from the file scanner and extracts the field position and data type of the unknown file format Unknown file format analysis system for performing software security testing, characterized in that it comprises a. 2. The unknown file format analysis system of claim 1, wherein the file scanner is a debugger that tracks a function when an unknown file is loaded into memory. 2. The unknown file format analysis system of claim 1, wherein the file analyzer compares the function parameter and the loaded file to extract field positions and data types of a file format. (a) monitoring the operation of a corresponding program loading a file unknown to memory in a file scanner; (b) parsing function parameters of the loaded file; (c) receiving the parsed information from a file analyzer to extract field positions and data types of unknown file formats; And (d) changing to a value for a defect operation in consideration of the extracted field position and data type Unknown file format analysis method for performing software security testing comprising a. The software security method of claim 4, wherein the step (b) is performed by dividing and extracting the file into a number type and a string type corresponding to the use of the file data in the stack. Unknown file format analysis method for performing testing. The method of claim 5, wherein the value of the function parameter corresponding to the number type and the string type is any one of an address, a number, and software-generated data indicating some data of a file in a memory. Unknown file format analysis method for performing software security testing, characterized in that it is defined. The method of claim 6, wherein when the value of the function parameter is an address indicating some data of a file in memory, the string is decomposed into a string in which the address value is used as it is in a string related function, or in a subsequent function call. An unknown file format analysis method for performing software security testing, characterized in that it is used as either a number of pieces or a data structure used as an address that points to arbitrary data. 7. The method according to claim 6, wherein when the value of the function parameter is a number, the position and the number of bytes in the number file are determined, and then the number and the number of times when the defect insertion is performed. Unknown file format analysis method for performing software security testing, characterized in that it performs an associated fault operation. 7. The method of claim 6, wherein if the value of the function parameter is software-generated data, it is used as an address that points to arbitrary data. The method according to any one of claims 5 to 9, wherein step (c) comprises: Performing a parameter check when invoking the function; Performing analysis for each case corresponding to the number of parameters of the function; And Storing the analysis result for each case Unknown file format analysis method for performing software security testing, characterized in that consisting of. 11. The method of claim 10, wherein when the case is an address indicating some data of a file in the memory, the location and range of the data area stored in the memory and a pointer to the data area are stored for later monitoring. Unknown file format analysis method for performing software security testing. 12. The method of claim 11, wherein the location and range of the data area stored in the memory and a pointer to the data area are used to extract a data type in a subsequent function call. How to analyze file formats. 12. The unknown file for performing software security testing according to claim 10, wherein when the case is used as a number, the field location and data type of the file including the value of the parameter are stored. Format analysis method. 11. The method of claim 10, wherein if the case is program generated data, the program generated data value is ignored.

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