Rating:

__BreakIn 2016 :: You Can(t) See Me__
================

_John Hammond_ | _Sunday, January 24, 2016_

> Honestly I do not have the challenge prompt or description. I will try to add it the moment I am able to retrieve it (it is currently not online).

----------

Admittedly, this challenge took a little bit of thought (though that is to be expected)!

We were given [this image](color.png) and that was the jist of our challenge. So, we got to work.

![The Image](color.png)

We reached for the usual low-hanging fruit: running [`strings`][strings] on the thing, [`exiftool`][exiftool], and [`stegsolve.jar`][stegsolve.jar]. No luck there. We tried turning it sideways to see if there were any clear letters we could pick out, or we tried to remove some of the colors and see if anything would jump out us a bit more easily...

But no, nothing.

Eventually, when we were just staring at [the image](color.png) in [`eog`][eog], we got this weird realization that the size of the image must be of some importance. It was odd that it was just 7 by 200 pixels... _it must be hiding [binary]_.

We then operated under the assumption that _every line_ was another [binary] number. The red color must have represented a [binary] `1` while the black must have represented a [binary] `0`. Immediately got started scripting something to pull all that data out.

Here's [the code we ended up with](get_flag.py):

``` python
#!/usr/bin/env python

from PIL import Image

pic = Image.open("color.png")
data = pic.load()

red = (255, 0, 0)

# We create an array to hold all the lines and start to loop through
# each pixel
binary_lines = []
width, height = pic.size
for y in xrange( height ):
binary_line = []
for x in xrange( width ):

pixel = data[x, y]

# We only have the two colors red and black, so I just test
#for one case and then use `else`.
if pixel == red:
binary_line.append( '1' )
else:
binary_line.append( '0' )

binary_lines.append( binary_line )

# A little 'list comprehension' magic to get the good stuff out...
ascii_text = ''.join([ chr(int(''.join(separated),2))
for separated in binary_lines ])
print ascii_text
```

And, believe it or not, the garbage that it spews out is actually our flag!

__The flag is `3xXKkFstTUpsG2IFDirE6xDrcAF8DSx4iWxd5f9IQ9T205izN8lS2MQUlsF11gT4TFXHHlLHVHprNTtrh6lURfdUW7Lpuzgu1VKzwb1bg1oq6Ae3GnykkLZZsnze3HVLxHlfCYtzyrcV2Oxp0Gb0Z2ELphR4Oxo7TyvHCuWKWlN8t8KIfHysZK7jBNPu6wRVEUPIwVra `.__

[netcat]: https://en.wikipedia.org/wiki/Netcat
[Wikipedia]: https://www.wikipedia.org/
[Linux]: https://www.linux.com/
[man page]: https://en.wikipedia.org/wiki/Man_page
[PuTTY]: http://www.putty.org/
[ssh]: https://en.wikipedia.org/wiki/Secure_Shell
[Windows]: http://www.microsoft.com/en-us/windows
[virtual machine]: https://en.wikipedia.org/wiki/Virtual_machine
[operating system]:https://en.wikipedia.org/wiki/Operating_system
[OS]: https://en.wikipedia.org/wiki/Operating_system
[VMWare]: http://www.vmware.com/
[VirtualBox]: https://www.virtualbox.org/
[hostname]: https://en.wikipedia.org/wiki/Hostname
[port number]: https://en.wikipedia.org/wiki/Port_%28computer_networking%29
[distribution]:https://en.wikipedia.org/wiki/Linux_distribution
[Ubuntu]: http://www.ubuntu.com/
[ISO]: https://en.wikipedia.org/wiki/ISO_image
[standard streams]: https://en.wikipedia.org/wiki/Standard_streams
[standard output]: https://en.wikipedia.org/wiki/Standard_streams
[standard input]: https://en.wikipedia.org/wiki/Standard_streams
[read]: http://ss64.com/bash/read.html
[variable]: https://en.wikipedia.org/wiki/Variable_%28computer_science%29
[command substitution]: http://www.tldp.org/LDP/abs/html/commandsub.html
[permissions]: https://en.wikipedia.org/wiki/File_system_permissions
[redirection]: http://www.tldp.org/LDP/abs/html/io-redirection.html
[pipe]: http://www.tldp.org/LDP/abs/html/io-redirection.html
[piping]: http://www.tldp.org/LDP/abs/html/io-redirection.html
[tmp]: http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/tmp.html
[curl]: http://curl.haxx.se/
[cl1p.net]: https://cl1p.net/
[request]: http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html
[POST request]: https://en.wikipedia.org/wiki/POST_%28HTTP%29
[Python]: http://python.org/
[interpreter]: https://en.wikipedia.org/wiki/List_of_command-line_interpreters
[requests]: http://docs.python-requests.org/en/latest/
[urllib]: https://docs.python.org/2/library/urllib.html
[file handling with Python]: https://docs.python.org/2/tutorial/inputoutput.html#reading-and-writing-files
[bash]: https://www.gnu.org/software/bash/
[Assembly]: https://en.wikipedia.org/wiki/Assembly_language
[the stack]: https://en.wikipedia.org/wiki/Stack_%28abstract_data_type%29
[register]: http://www.tutorialspoint.com/assembly_programming/assembly_registers.htm
[hex]: https://en.wikipedia.org/wiki/Hexadecimal
[hexadecimal]: https://en.wikipedia.org/wiki/Hexadecimal
[archive file]: https://en.wikipedia.org/wiki/Archive_file
[zip file]: https://en.wikipedia.org/wiki/Zip_%28file_format%29
[zip files]: https://en.wikipedia.org/wiki/Zip_%28file_format%29
[.zip]: https://en.wikipedia.org/wiki/Zip_%28file_format%29
[gigabytes]: https://en.wikipedia.org/wiki/Gigabyte
[GB]: https://en.wikipedia.org/wiki/Gigabyte
[GUI]: https://en.wikipedia.org/wiki/Graphical_user_interface
[Wireshark]: https://www.wireshark.org/
[FTP]: https://en.wikipedia.org/wiki/File_Transfer_Protocol
[client and server]: https://simple.wikipedia.org/wiki/Client-server
[RETR]: http://cr.yp.to/ftp/retr.html
[FTP server]: https://help.ubuntu.com/lts/serverguide/ftp-server.html
[SFTP]: https://en.wikipedia.org/wiki/SSH_File_Transfer_Protocol
[SSL]: https://en.wikipedia.org/wiki/Transport_Layer_Security
[encryption]: https://en.wikipedia.org/wiki/Encryption
[HTML]: https://en.wikipedia.org/wiki/HTML
[Flask]: http://flask.pocoo.org/
[SQL]: https://en.wikipedia.org/wiki/SQL
[and]: https://en.wikipedia.org/wiki/Logical_conjunction
[Cyberstakes]: https://cyberstakesonline.com/
[cat]: https://en.wikipedia.org/wiki/Cat_%28Unix%29
[symbolic link]: https://en.wikipedia.org/wiki/Symbolic_link
[ln]: https://en.wikipedia.org/wiki/Ln_%28Unix%29
[absolute path]: https://en.wikipedia.org/wiki/Path_%28computing%29
[CTF]: https://en.wikipedia.org/wiki/Capture_the_flag#Computer_security
[Cyberstakes]: https://cyberstakesonline.com/
[OverTheWire]: http://overthewire.org/
[Leviathan]: http://overthewire.org/wargames/leviathan/
[ls]: https://en.wikipedia.org/wiki/Ls
[grep]: https://en.wikipedia.org/wiki/Grep
[strings]: http://linux.die.net/man/1/strings
[ltrace]: http://linux.die.net/man/1/ltrace
[C]: https://en.wikipedia.org/wiki/C_%28programming_language%29
[strcmp]: http://linux.die.net/man/3/strcmp
[access]: http://pubs.opengroup.org/onlinepubs/009695399/functions/access.html
[system]: http://linux.die.net/man/3/system
[real user ID]: https://en.wikipedia.org/wiki/User_identifier
[effective user ID]: https://en.wikipedia.org/wiki/User_identifier
[brute force]: https://en.wikipedia.org/wiki/Brute-force_attack
[for loop]: https://en.wikipedia.org/wiki/For_loop
[bash programming]: http://tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html
[Behemoth]: http://overthewire.org/wargames/behemoth/
[command line]: https://en.wikipedia.org/wiki/Command-line_interface
[command-line]: https://en.wikipedia.org/wiki/Command-line_interface
[cli]: https://en.wikipedia.org/wiki/Command-line_interface
[PHP]: https://php.net/
[URL]: https://en.wikipedia.org/wiki/Uniform_Resource_Locator
[TamperData]: https://addons.mozilla.org/en-US/firefox/addon/tamper-data/
[Firefox]: https://www.mozilla.org/en-US/firefox/new/?product=firefox-3.6.8&os=osx%E2%8C%A9=en-US
[Caesar Cipher]: https://en.wikipedia.org/wiki/Caesar_cipher
[Google Reverse Image Search]: https://www.google.com/imghp
[PicoCTF]: https://picoctf.com/
[PicoCTF 2014]: https://picoctf.com/
[JavaScript]: https://www.javascript.com/
[base64]: https://en.wikipedia.org/wiki/Base64
[client-side]: https://en.wikipedia.org/wiki/Client-side_scripting
[client side]: https://en.wikipedia.org/wiki/Client-side_scripting
[javascript:alert]: http://www.w3schools.com/js/js_popup.asp
[Java]: https://www.java.com/en/
[2147483647]: https://en.wikipedia.org/wiki/2147483647_%28number%29
[XOR]: https://en.wikipedia.org/wiki/Exclusive_or
[XOR cipher]: https://en.wikipedia.org/wiki/XOR_cipher
[quipqiup.com]: http://www.quipqiup.com/
[PDF]: https://en.wikipedia.org/wiki/Portable_Document_Format
[pdfimages]: http://linux.die.net/man/1/pdfimages
[ampersand]: https://en.wikipedia.org/wiki/Ampersand
[URL encoding]: https://en.wikipedia.org/wiki/Percent-encoding
[Percent encoding]: https://en.wikipedia.org/wiki/Percent-encoding
[URL-encoding]: https://en.wikipedia.org/wiki/Percent-encoding
[Percent-encoding]: https://en.wikipedia.org/wiki/Percent-encoding
[endianness]: https://en.wikipedia.org/wiki/Endianness
[ASCII]: https://en.wikipedia.org/wiki/ASCII
[struct]: https://docs.python.org/2/library/struct.html
[pcap]: https://en.wikipedia.org/wiki/Pcap
[packet capture]: https://en.wikipedia.org/wiki/Packet_analyzer
[HTTP]: https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol
[Wireshark filters]: https://wiki.wireshark.org/DisplayFilters
[SSL]: https://en.wikipedia.org/wiki/Transport_Layer_Security
[Assembly]: https://en.wikipedia.org/wiki/Assembly_language
[Assembly Syntax]: https://en.wikipedia.org/wiki/X86_assembly_language#Syntax
[Intel Syntax]: https://en.wikipedia.org/wiki/X86_assembly_language
[Intel or AT&T]: http://www.imada.sdu.dk/Courses/DM18/Litteratur/IntelnATT.htm
[AT&T syntax]: https://en.wikibooks.org/wiki/X86_Assembly/GAS_Syntax
[GET request]: https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Request_methods
[GET requests]: https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Request_methods
[IP Address]: https://en.wikipedia.org/wiki/IP_address
[IP Addresses]: https://en.wikipedia.org/wiki/IP_address
[MAC Address]: https://en.wikipedia.org/wiki/MAC_address
[session]: https://en.wikipedia.org/wiki/Session_%28computer_science%29
[Cookie Manager+]: https://addons.mozilla.org/en-US/firefox/addon/cookies-manager-plus/
[hexedit]: http://linux.die.net/man/1/hexedit
[Google]: http://google.com/
[Scapy]: http://www.secdev.org/projects/scapy/
[ARP]: https://en.wikipedia.org/wiki/Address_Resolution_Protocol
[UDP]: https://en.wikipedia.org/wiki/User_Datagram_Protocol
[SQL injection]: https://en.wikipedia.org/wiki/SQL_injection
[sqlmap]: http://sqlmap.org/
[sqlite]: https://www.sqlite.org/
[MD5]: https://en.wikipedia.org/wiki/MD5
[OpenSSL]: https://www.openssl.org/
[Burpsuite]:https://portswigger.net/burp/
[Burpsuite.jar]:https://portswigger.net/burp/
[Burp]:https://portswigger.net/burp/
[NULL character]: https://en.wikipedia.org/wiki/Null_character
[Format String Vulnerability]: http://www.cis.syr.edu/~wedu/Teaching/cis643/LectureNotes_New/Format_String.pdf
[printf]: http://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html
[argument]: https://en.wikipedia.org/wiki/Parameter_%28computer_programming%29
[arguments]: https://en.wikipedia.org/wiki/Parameter_%28computer_programming%29
[parameter]: https://en.wikipedia.org/wiki/Parameter_%28computer_programming%29
[parameters]: https://en.wikipedia.org/wiki/Parameter_%28computer_programming%29
[Vortex]: http://overthewire.org/wargames/vortex/
[socket]: https://docs.python.org/2/library/socket.html
[file descriptor]: https://en.wikipedia.org/wiki/File_descriptor
[file descriptors]: https://en.wikipedia.org/wiki/File_descriptor
[Forth]: https://en.wikipedia.org/wiki/Forth_%28programming_language%29
[github]: https://github.com/
[buffer overflow]: https://en.wikipedia.org/wiki/Buffer_overflow
[try harder]: https://www.offensive-security.com/when-things-get-tough/
[segmentation fault]: https://en.wikipedia.org/wiki/Segmentation_fault
[seg fault]: https://en.wikipedia.org/wiki/Segmentation_fault
[segfault]: https://en.wikipedia.org/wiki/Segmentation_fault
[shellcode]: https://en.wikipedia.org/wiki/Shellcode
[sploit-tools]: https://github.com/SaltwaterC/sploit-tools
[Kali]: https://www.kali.org/
[Kali Linux]: https://www.kali.org/
[gdb]: https://www.gnu.org/software/gdb/
[gdb tutorial]: http://www.unknownroad.com/rtfm/gdbtut/gdbtoc.html
[payload]: https://en.wikipedia.org/wiki/Payload_%28computing%29
[peda]: https://github.com/longld/peda
[git]: https://git-scm.com/
[home directory]: https://en.wikipedia.org/wiki/Home_directory
[NOP slide]:https://en.wikipedia.org/wiki/NOP_slide
[NOP]: https://en.wikipedia.org/wiki/NOP
[examine]: https://sourceware.org/gdb/onlinedocs/gdb/Memory.html
[stack pointer]: http://stackoverflow.com/questions/1395591/what-is-exactly-the-base-pointer-and-stack-pointer-to-what-do-they-point
[little endian]: https://en.wikipedia.org/wiki/Endianness
[big endian]: https://en.wikipedia.org/wiki/Endianness
[endianness]: https://en.wikipedia.org/wiki/Endianness
[pack]: https://docs.python.org/2/library/struct.html#struct.pack
[ash]:https://en.wikipedia.org/wiki/Almquist_shell
[dash]: https://en.wikipedia.org/wiki/Almquist_shell
[shell]: https://en.wikipedia.org/wiki/Shell_%28computing%29
[pwntools]: https://github.com/Gallopsled/pwntools
[colorama]: https://pypi.python.org/pypi/colorama
[objdump]: https://en.wikipedia.org/wiki/Objdump
[UPX]: http://upx.sourceforge.net/
[64-bit]: https://en.wikipedia.org/wiki/64-bit_computing
[breakpoint]: https://en.wikipedia.org/wiki/Breakpoint
[stack frame]: http://www.cs.umd.edu/class/sum2003/cmsc311/Notes/Mips/stack.html
[format string]: http://codearcana.com/posts/2013/05/02/introduction-to-format-string-exploits.html
[format specifiers]: http://web.eecs.umich.edu/~bartlett/printf.html
[format specifier]: http://web.eecs.umich.edu/~bartlett/printf.html
[variable expansion]: https://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html
[base pointer]: http://stackoverflow.com/questions/1395591/what-is-exactly-the-base-pointer-and-stack-pointer-to-what-do-they-point
[dmesg]: https://en.wikipedia.org/wiki/Dmesg
[Android]: https://www.android.com/
[.apk]:https://en.wikipedia.org/wiki/Android_application_package
[apk]:https://en.wikipedia.org/wiki/Android_application_package
[decompiler]: https://en.wikipedia.org/wiki/Decompiler
[decompile Java code]: http://www.javadecompilers.com/
[jadx]: https://github.com/skylot/jadx
[.img]: https://en.wikipedia.org/wiki/IMG_%28file_format%29
[binwalk]: http://binwalk.org/
[JPEG]: https://en.wikipedia.org/wiki/JPEG
[JPG]: https://en.wikipedia.org/wiki/JPEG
[disk image]: https://en.wikipedia.org/wiki/Disk_image
[foremost]: http://foremost.sourceforge.net/
[eog]: https://wiki.gnome.org/Apps/EyeOfGnome
[function pointer]: https://en.wikipedia.org/wiki/Function_pointer
[machine code]: https://en.wikipedia.org/wiki/Machine_code
[compiled language]: https://en.wikipedia.org/wiki/Compiled_language
[compiler]: https://en.wikipedia.org/wiki/Compiler
[compile]: https://en.wikipedia.org/wiki/Compiler
[scripting language]: https://en.wikipedia.org/wiki/Scripting_language
[shell-storm.org]: http://shell-storm.org/
[shell-storm]:http://shell-storm.org/
[shellcode database]: http://shell-storm.org/shellcode/
[gdb-peda]: https://github.com/longld/peda
[x86]: https://en.wikipedia.org/wiki/X86
[Intel x86]: https://en.wikipedia.org/wiki/X86
[sh]: https://en.wikipedia.org/wiki/Bourne_shell
[/bin/sh]: https://en.wikipedia.org/wiki/Bourne_shell
[SANS]: https://www.sans.org/
[Holiday Hack Challenge]: https://holidayhackchallenge.com/
[USCGA]: http://uscga.edu/
[United States Coast Guard Academy]: http://uscga.edu/
[US Coast Guard Academy]: http://uscga.edu/
[Academy]: http://uscga.edu/
[Coast Guard Academy]: http://uscga.edu/
[Hackfest]: https://www.sans.org/event/pen-test-hackfest-2015
[SSID]: https://en.wikipedia.org/wiki/Service_set_%28802.11_network%29
[DNS]: https://en.wikipedia.org/wiki/Domain_Name_System
[Python:base64]: https://docs.python.org/2/library/base64.html
[OpenWRT]: https://openwrt.org/
[node.js]: https://nodejs.org/en/
[MongoDB]: https://www.mongodb.org/
[Mongo]: https://www.mongodb.org/
[SuperGnome 01]: http://52.2.229.189/
[Shodan]: https://www.shodan.io/
[SuperGnome 02]: http://52.34.3.80/
[SuperGnome 03]: http://52.64.191.71/
[SuperGnome 04]: http://52.192.152.132/
[SuperGnome 05]: http://54.233.105.81/
[Local file inclusion]: http://hakipedia.com/index.php/Local_File_Inclusion
[LFI]: http://hakipedia.com/index.php/Local_File_Inclusion
[PNG]: http://www.libpng.org/pub/png/
[.png]: http://www.libpng.org/pub/png/
[Remote Code Execution]: https://en.wikipedia.org/wiki/Arbitrary_code_execution
[RCE]: https://en.wikipedia.org/wiki/Arbitrary_code_execution
[GNU]: https://www.gnu.org/
[regular expression]: https://en.wikipedia.org/wiki/Regular_expression
[regular expressions]: https://en.wikipedia.org/wiki/Regular_expression
[uniq]: https://en.wikipedia.org/wiki/Uniq
[sort]: https://en.wikipedia.org/wiki/Sort_%28Unix%29
[binary data]: https://en.wikipedia.org/wiki/Binary_data
[binary]: https://en.wikipedia.org/wiki/Binary
[Firebug]: http://getfirebug.com/
[SHA1]: https://en.wikipedia.org/wiki/SHA-1
[SHA-1]: https://en.wikipedia.org/wiki/SHA-1
[Linux]: https://www.linux.com/
[Ubuntu]: http://www.ubuntu.com/
[Kali Linux]: https://www.kali.org/
[Over The Wire]: http://overthewire.org/wargames/
[OverTheWire]: http://overthewire.org/wargames/
[Micro Corruption]: https://microcorruption.com/
[Smash The Stack]: http://smashthestack.org/
[CTFTime]: https://ctftime.org/
[Writeups]: https://ctftime.org/writeups
[Competitions]: https://ctftime.org/event/list/upcoming
[Skull Security]: https://wiki.skullsecurity.org/index.php?title=Main_Page
[MITRE]: http://mitrecyberacademy.org/
[Trail of Bits]: https://trailofbits.github.io/ctf/
[Stegsolve]: http://www.caesum.com/handbook/Stegsolve.jar
[stegsolve.jar]: http://www.caesum.com/handbook/Stegsolve.jar
[Steghide]: http://steghide.sourceforge.net/
[IDA Pro]: https://www.hex-rays.com/products/ida/
[Wireshark]: https://www.wireshark.org/
[Bro]: https://www.bro.org/
[Meterpreter]: https://www.offensive-security.com/metasploit-unleashed/about-meterpreter/
[Metasploit]: http://www.metasploit.com/
[Burpsuite]: https://portswigger.net/burp/
[xortool]: https://github.com/hellman/xortool
[sqlmap]: http://sqlmap.org/
[VMWare]: http://www.vmware.com/
[VirtualBox]: https://www.virtualbox.org/wiki/Downloads
[VBScript Decoder]: https://gist.github.com/bcse/1834878
[quipqiup.com]: http://quipqiup.com/
[EXIFTool]: http://www.sno.phy.queensu.ca/~phil/exiftool/
[Scalpel]: https://github.com/sleuthkit/scalpel
[Ryan's Tutorials]: http://ryanstutorials.net
[Linux Fundamentals]: http://linux-training.be/linuxfun.pdf
[USCGA]: http://uscga.edu
[Cyberstakes]: https://cyberstakesonline.com/
[Crackmes.de]: http://crackmes.de/
[Nuit Du Hack]: http://wargame.nuitduhack.com/
[Hacking-Lab]: https://www.hacking-lab.com/index.html
[FlareOn]: http://www.flare-on.com/
[The Second Extended Filesystem]: http://www.nongnu.org/ext2-doc/ext2.html
[GIF]: https://en.wikipedia.org/wiki/GIF
[PDFCrack]: http://pdfcrack.sourceforge.net/index.html
[Hexcellents CTF Knowledge Base]: http://security.cs.pub.ro/hexcellents/wiki/home
[GDB]: https://www.gnu.org/software/gdb/
[The Linux System Administrator's Guide]: http://www.tldp.org/LDP/sag/html/index.html
[aeskeyfind]: https://citp.princeton.edu/research/memory/code/
[rsakeyfind]: https://citp.princeton.edu/research/memory/code/
[Easy Python Decompiler]: http://sourceforge.net/projects/easypythondecompiler/
[factordb.com]: http://factordb.com/
[Volatility]: https://github.com/volatilityfoundation/volatility
[Autopsy]: http://www.sleuthkit.org/autopsy/
[ShowMyCode]: http://www.showmycode.com/
[HTTrack]: https://www.httrack.com/
[theHarvester]: https://github.com/laramies/theHarvester
[Netcraft]: http://toolbar.netcraft.com/site_report/
[Nikto]: https://cirt.net/Nikto2
[PIVOT Project]: http://pivotproject.org/
[InsomniHack PDF]: http://insomnihack.ch/wp-content/uploads/2016/01/Hacking_like_in_the_movies.pdf
[radare]: http://www.radare.org/r/
[radare2]: http://www.radare.org/r/
[foremost]: https://en.wikipedia.org/wiki/Foremost_%28software%29
[ZAP]: https://github.com/zaproxy/zaproxy
[Computer Security Student]: https://www.computersecuritystudent.com/HOME/index.html
[Vulnerable Web Page]: http://testphp.vulnweb.com/
[Hipshot]: https://bitbucket.org/eliteraspberries/hipshot
[John the Ripper]: https://en.wikipedia.org/wiki/John_the_Ripper
[hashcat]: http://hashcat.net/oclhashcat/
[fcrackzip]: http://manpages.ubuntu.com/manpages/hardy/man1/fcrackzip.1.html
[Whitehatters Academy]: https://www.whitehatters.academy/
[gn00bz]: http://gnoobz.com/
[Command Line Kung Fu]:http://blog.commandlinekungfu.com/
[Cybrary]: https://www.cybrary.it/
[Obum Chidi]: https://obumchidi.wordpress.com/
[ksnctf]: http://ksnctf.sweetduet.info/
[ToolsWatch]: http://www.toolswatch.org/category/tools/
[Net Force]:https://net-force.nl/
[Nandy Narwhals]: http://nandynarwhals.org/
[CTFHacker]: http://ctfhacker.com/
[Tasteless]: http://tasteless.eu/
[Dragon Sector]: http://blog.dragonsector.pl/
[pwnable.kr]: http://pwnable.kr/
[reversing.kr]: http://reversing.kr/
[DVWA]: http://www.dvwa.co.uk/
[Damn Vulnerable Web App]: http://www.dvwa.co.uk/
[b01lers]: https://b01lers.net/
[Capture the Swag]: https://ctf.rip/
[pointer]: https://en.wikipedia.org/wiki/Pointer_%28computer_programming%29
[call stack]: https://en.wikipedia.org/wiki/Call_stack
[return statement]: https://en.wikipedia.org/wiki/Return_statement
[return address]: https://en.wikipedia.org/wiki/Return_statement
[disassemble]: https://en.wikipedia.org/wiki/Disassembler
[less]: https://en.wikipedia.org/wiki/Less_%28Unix%29
[puts]: http://pubs.opengroup.org/onlinepubs/009695399/functions/puts.html
[disassembly]: https://en.wikibooks.org/wiki/X86_Disassembly
[PLT]: https://www.technovelty.org/linux/plt-and-got-the-key-to-code-sharing-and-dynamic-libraries.html
[Procedure Lookup Table]: http://reverseengineering.stackexchange.com/questions/1992/what-is-plt-got
[environment variable]: https://en.wikipedia.org/wiki/Environment_variable
[getenvaddr]: https://code.google.com/p/protostar-solutions/source/browse/Stack+6/getenvaddr.c?r=3d0a6873d44901d63caf9ad3764cfb9ab47f3332
[getenvaddr.c]: https://code.google.com/p/protostar-solutions/source/browse/Stack+6/getenvaddr.c?r=3d0a6873d44901d63caf9ad3764cfb9ab47f3332

Original writeup (https://github.com/objEEdump/breakin/tree/master/you_cant_see_me).