Rating:

Flagception
========

> John Hammond | Tuesday, February 7th, 2017

--------------------------------------------

> Yo dawg, I heard you like flags
>
> So I put a flag in your flag
>
> Flag format: BITSCTF{a1phanum3r1c_w0rds}

This challenge was really intimidating because there was no link or download or really anything to work with; it was super vague and open-ended.

Usually that means the challenge is referring to something on the [CTF] game site, like a web page source or a logo or something.

That led me to look at their logo...

And the _do_ have a flag in their logo.

![logo.png](logo.png)

With some further inspection, I saw some peculiar colors in that flag...

![zoomin.png](zoomin.png)

Some of the pixels in the top-left corner are darker in the other! The width is about `8` for those strange pixels... this must be a bunch of bytes represented in binary.

I cut those out with a `1` being the darker color and a `0` being the lighter color.

Then I cooked it in [Python]:

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

print ''.join([chr(int(i,2)) for i in '1000010 1001001 1010100 1010011 1000011 1010100 1000110 1111011 1100110 0110001 1100001 1100111 1100011 0110011 1110000 1110100 0110001 0110000 1101110 1111101'.split(' ')])
```

Bah.

__The flag was: `BITSCTF{f1agc3pt10n}`__

[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
[man pages]: https://en.wikipedia.org/wiki/Man_page
[man]: 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
[port]: https://en.wikipedia.org/wiki/Port_%28computer_networking%29
[ports]: 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
[redirect]: http://www.tldp.org/LDP/abs/html/io-redirection.html
[pipe]: http://www.tldp.org/LDP/abs/html/io-redirection.html
[piped]: 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]: 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
[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/
[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
[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
[scripting language]: https://en.wikipedia.org/wiki/Scripting_language
[scripts]: https://en.wikipedia.org/wiki/Scripting_language
[script]: 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
[automation is divine]: https://www.youtube.com/watch?v=36AA3JGRP9s
[repos]:https://help.ubuntu.com/community/Repositories/Ubuntu
[repo]:https://help.ubuntu.com/community/Repositories/Ubuntu
[repository]:https://help.ubuntu.com/community/Repositories/Ubuntu
[repositories]: https://help.ubuntu.com/community/Repositories/Ubuntu
[hex dump]: https://en.wikipedia.org/wiki/Hex_dump
[hexdump]: https://en.wikipedia.org/wiki/Hex_dump
[xxd]: http://linuxcommand.org/man_pages/xxd1.html
[mkdir]: https://en.wikipedia.org/wiki/Mkdir
[file]: https://en.wikipedia.org/wiki/File_%28command%29
[gzip]: http://www.gzip.org/
[file extension]: https://en.wikipedia.org/wiki/Filename_extension
[bzip]: http://www.bzip.org/
[bzip2]: http://www.bzip.org/
[tar]: https://en.wikipedia.org/wiki/Tar_%28computing%29
[tar command]: http://linuxcommand.org/man_pages/tar1.html
[private key]: https://help.ubuntu.com/community/SSH/OpenSSH/Keys
[s_client]: https://www.openssl.org/docs/manmaster/apps/s_client.html
[nmap]: https://nmap.org/
[IP address]: https://en.wikipedia.org/wiki/IP_address
[RSA]: https://en.wikipedia.org/wiki/RSA_(cryptosystem)
[ssh private key]: https://help.ubuntu.com/community/SSH/OpenSSH/Keys
[file permissions]: https://www.linux.com/learn/understanding-linux-file-permissions
[octal file permission]: http://www.cyberciti.biz/faq/how-linux-file-permissions-work/
[octal file permissions]: http://www.cyberciti.biz/faq/how-linux-file-permissions-work/
[chmod]: https://en.wikipedia.org/wiki/Chmod
[diff]: http://man7.org/linux/man-pages/man1/diff.1.html
[.bashrc]: http://unix.stackexchange.com/questions/129143/what-is-the-purpose-of-bashrc-and-how-does-it-work
[bashrc]: http://unix.stackexchange.com/questions/129143/what-is-the-purpose-of-bashrc-and-how-does-it-work
[setuid]: https://en.wikipedia.org/wiki/Setuid
[user id]: https://en.wikipedia.org/wiki/User_identifier
[effective user id]: https://en.wikipedia.org/wiki/User_identifier#Effective_user_ID
[cron]: https://en.wikipedia.org/wiki/Cron
[file extension]: https://en.wikipedia.org/wiki/Filename_extension
[file extensions]: https://en.wikipedia.org/wiki/Filename_extension
[bash script]: https://linuxconfig.org/bash-scripting-tutorial
[bash script]: https://linuxconfig.org/bash-scripting-tutorial
[bash scripts]: https://linuxconfig.org/bash-scripting-tutorial
[shebang line]: https://en.wikipedia.org/wiki/Shebang_(Unix)
[she-bang line]: https://en.wikipedia.org/wiki/Shebang_(Unix)
[sha-bang line]: https://en.wikipedia.org/wiki/Shebang_(Unix)
[shabang line]: https://en.wikipedia.org/wiki/Shebang_(Unix)
[sha bang line]: https://en.wikipedia.org/wiki/Shebang_(Unix)
[nano]: https://en.wikipedia.org/wiki/GNU_nano
[text editor]: https://en.wikipedia.org/wiki/Text_editor
[whoami]: https://en.wikipedia.org/wiki/Whoami
[echo]: https://en.wikipedia.org/wiki/Echo_(command)
[md5sum]: http://www.tutorialspoint.com/unix_commands/md5sum.htm
[checksum]: https://en.wikipedia.org/wiki/Checksum
[hash]: https://en.wikipedia.org/wiki/Cryptographic_hash_function
[cut]: https://en.wikipedia.org/wiki/Cut_(Unix)
[daemon]: https://en.wikipedia.org/wiki/Daemon_(computing)
[temporary directory]: https://en.wikipedia.org/wiki/Temporary_folder
[temp directory]: https://en.wikipedia.org/wiki/Temporary_folder
[temp folder]: https://en.wikipedia.org/wiki/Temporary_folder
[temporary folder]: https://en.wikipedia.org/wiki/Temporary_folder
[seq]: http://www.cyberciti.biz/tips/tag/seq-command
[/etc/passwd]: https://en.wikipedia.org/wiki/Passwd#Password_file
[more]: https://en.wikipedia.org/wiki/More_(command)
[vi]: https://en.wikipedia.org/wiki/Vi
[vim]: http://www.vim.org/
[caesar cipher]: https://en.wikipedia.org/wiki/Caesar_cipher
[vignere cipher]: https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher
[substitution cipher]: https://en.wikipedia.org/wiki/Substitution_cipher
[DNA]: https://en.wikipedia.org/wiki/Nucleic_acid_sequence
[Python bytecode]: http://security.coverity.com/blog/2014/Nov/understanding-python-bytecode.html
[uncompyle]: https://github.com/gstarnberger/uncompyle
[Easy Python Decompiler]: https://github.com/aliansi/Easy-Python-Decompiler-v1.3.2
[marshal]: https://docs.python.org/2/library/marshal.html
[IDLE]: https://en.wikipedia.org/wiki/IDLE
[bytecode]: http://whatis.techtarget.com/definition/bytecode
[dis]: https://docs.python.org/2/library/dis.html
[rot13]: https://en.wikipedia.org/wiki/ROT13
[calendar]: https://docs.python.org/2/library/calendar.html
[datetime]: https://docs.python.org/2/library/datetime.html
[primefac]: https://pypi.python.org/pypi/primefac
[re]: https://docs.python.org/2/library/re.html
[IDA pro]: https://www.hex-rays.com/products/ida/
[IDA]: https://www.hex-rays.com/products/ida/
[QR Code]: https://en.wikipedia.org/wiki/QR_code
[RGB]: https://en.wikipedia.org/wiki/RGB_color_model
[RGB color]: https://en.wikipedia.org/wiki/RGB_color_model
[exiftool]: http://www.sno.phy.queensu.ca/~phil/exiftool/
[robots.txt]: http://www.robotstxt.org/
[XSS]: https://en.wikipedia.org/wiki/Cross-site_scripting
[cross-site scripting]: https://en.wikipedia.org/wiki/Cross-site_scripting
[cross site scripting]: https://en.wikipedia.org/wiki/Cross-site_scripting
[cookie catcher]: http://hackwithstyle.blogspot.com/2011/11/what-is-cookie-catcher-and-how-to-get.html
[johnhammond.org]: http://johnhammond.org
[HTTP cookie]: https://en.wikipedia.org/wiki/HTTP_cookie
[HTTP cookies]: https://en.wikipedia.org/wiki/HTTP_cookie
[cookie]: https://en.wikipedia.org/wiki/HTTP_cookie
[cookies]: https://en.wikipedia.org/wiki/HTTP_cookie
[HTTP GET]: http://www.w3schools.com/Tags/ref_httpmethods.asp
[tee]: https://en.wikipedia.org/wiki/Tee_(command)
[reverse engineering]: https://en.wikipedia.org/wiki/Reverse_engineering
[cryptography]: https://en.wikipedia.org/wiki/Cryptography
[crypto]: https://en.wikipedia.org/wiki/Cryptography
[sed]: https://en.wikipedia.org/wiki/Sed
[padding]: https://en.wikipedia.org/wiki/Padding_(cryptography)
[xortool]: https://github.com/hellman/xortool
[XOR Cracker]: https://wiremask.eu/tools/xor-cracker/

Original writeup (https://github.com/USCGA/writeups/tree/master/online_ctfs/bitsctf_2017/flagception).