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examiner

NAME

examiner - A ELF binary executable analyzer

SYNOPSIS

examiner [ -hvVsHRLq ] [ -d directory ] [ -C coroner.conf ] [ -o outfile ] [ -c 'comment char' ] -x executable

DESCRIPTION

The examiner is a program used to analyze and comment on ELF executables. Its purpose is mainly intended for forensic analysis but can be used for general reverse engineering. The goal is to take a foreign executable and analyze it without running it. The examiner relies on objdump to do its disassembly and then it parses the assembly output and attempts to put human readable comments to help facilitate analysis of the binary.

The commented file will be created with the name of the target binary with the extension of .commented. By default the Examiner creates $HOME/examiner-data directory to store its output. This can be overridden with the -d option. Also if The Coroners Toolkit (TCT) is installed the examiner will use the directory specified by TCT. See below for more information for using the Examiner with TCT. You may use the -o option to specify a seperate file for the commented source. If you use -o - Then Examiner will print the commented source to STDOUT.

The examiner requires that you use the -x option to specify an executable to analyze. By default the examiner only reports what Phase of analysis it is currently working on. The examiner analyzes binaries in four phases.

PHASE 1 - Initial analysis and parsing

PHASE 2 - Passes over the information and collects info

PHASE 3 - Manipulates collected data to draw conclusions

PHASE 4 - Generate the commented output

If the -v option is used then the program will report on each step within the phase as well. You can also have a brief summary reported that will give you some information about the total number of functions found, etc. If you don't want any output you can use the -q option.

The examiner will attempt to read ASCII strings from the .rodata section headers. It will then cross references this information in its output. It attempts to only print the printable characters and display hex or C style representations for special characters such as '\n'. In the commented output the examiner will restrict the length of the string. This feature can be overridden with the -L option. This is really not recommended.

You can generate additional reports that may help in analysis. If the -H option is supplied it will dump each section in the executable. The files are stored in the working directory. These files will have the target executables name with the section as an extension, eg: binary.rodata.

You can generate Reference files with the -R option. These files are generated for help in cross referencing information. Currently it will create three files: functions, interrupts, and sections. The function file contains the guessed function name and it's address. The interrupts file list any interrupts that are called and what the stack would look like at the time (sort of). The section file contains a list of all section and their memory ranges.

For a brief summary of all the options you can use the -h option. If you supply the -V option examiner will print its version info and then exit.

USING EXAMINER WITH TCT

The examiner can optionally be run on a system that has The Coroners Toolkit (TCT) installed. The Examiner will use some executables when the are installed. The paths to these may be specified in TCT paths.pl file. The Examiner will also read in the coroner.conf file to locate the section it should use as its working directory. You can specify a different coroner.conf file with the -C option.

The newer version of the Examiner will read in an optional hash library. This library is simply hash references that would normally be generated by parsing the net.h and unistd.h files. This file examiner_hashes.pl will be parsed if its in the current directory or /usr/share/tct. unistd.h is substituted for syscall.h on BSD based systems. Check the os directory for some pre-created examiner hashes.

FILES

coroner.conf - (optional conf file)

examiner_hashes.pl - (optional) If present won't parse header files

LICENSE

The program is copyrighted by Craig Smith under the terms of the GPL

AUTHOR(s)

Craig Smith