OverTheWire - Bandit

Level0

Level Goal

The password for the next level is stored in a file called readme located in the home directory. Use this password to log into bandit1 using SSH. Whenever you find a password for a level, use SSH (on port 2220) to log into that level and continue the game.

解答

ssh -p 2220 bandit0@bandit.labs.overthewire.org連進bandit0主機
ls看到檔案readme
cat檔案拿到flag

Level1

Level Goal

The password for the next level is stored in a file called - located in the home directory

解答

先ls發現有一個檔案-
嘗試用cat打開，但沒辦法
下pwd看絕對路徑/home/bandit1

Level2

Level Goal

The password for the next level is stored in a file called spaces in this filename located in the home directory

解答

ls看到檔案spaces in this filename直接cat取flag

Level3

Level Goal

The password for the next level is stored in a hidden file in the inhere directory.

解答

先進入inhere目錄
ls顯示沒東西，加參數ls -al看到.hidden
cat取flag

Level4

Level Goal

The password for the next level is stored in the only human-readable file in the inhere directory. Tip: if your terminal is messed up, try the “reset” command.

解答

先進入/inhere目錄
ls顯示出有10個檔案
file ./* 顯示副檔名
cat ./-file07打開檔案

Level5

Level Goal

The password for the next level is stored in a file somewhere under the inhere directory and has all of the following properties:

解答

human-readable
1033 bytes in size
not executable

先進入/inhere目錄
按照題目題示查找檔案

Level6

Level Goal

解答

The password for the next level is stored somewhere on the server and has all of the following properties:

owned by user bandit7
owned by group bandit6
33 bytes in size

按照題目設條件

Level7

Level Goal

The password for the next level is stored in the file data.txt next to the word millionth

解答

按照題目條件在 data.txt 查找密碼

Level8

Level Goal

The password for the next level is stored in the file data.txt and is the only line of text that occurs only once

解答

先用sort排列後再用uniq -u輸出沒有重複的字串

Level9

Level Goal

The password for the next level is stored in the file data.txt in one of the few human-readable strings, preceded by several ‘=’ characters.

解答

用strings過濾可閱讀的文字,再用grep找出開頭是=的字串

Level10

Level Goal

The password for the next level is stored in the file data.txt, which contains base64 encoded data

解答

用base64 -d 解碼

Level11

Level Goal

The password for the next level is stored in the file data.txt, where all lowercase (a-z) and uppercase (A-Z) letters have been rotated by 13 positions

解答

用 tr 'A-Za-z' 'N-ZA-Mn-za-m'轉換字元解密RO13

Level12

Level Goal

The password for the next level is stored in the file data.txt, which is a hexdump of a file that has been repeatedly compressed. For this level it may be useful to create a directory under /tmp in which you can work using mkdir. For example: mkdir /tmp/myname123. Then copy the datafile using cp, and rename it using mv (read the manpages!)

解答

先將檔案移到myname123cp /home/bandit12/data.txt /tmp/myname123
用xxd -r轉換進位
再用file看壓縮類型
分別用gzip -d bzip2 -d tar xvf解壓縮

Level13

Level Goal

The password for the next level is stored in /etc/bandit_pass/bandit14 and can only be read by user bandit14. For this level, you don’t get the next password, but you get a private SSH key that can be used to log into the next level. Note: localhost is a hostname that refers to the machine you are working on

解答

先將 sshkey.private 中的key複製
到本機端cat > 檔名把key存入後提權chmod 600 檔名
再用ssh -i 檔名 bandit14@bandit.labs.overthewire.org -p 2220用檔案中的key連線

Level14

Level Goal

The password for the next level can be retrieved by submitting the password of the current level to port 30000 on localhost.

解答

先從上一題給的路徑/etc/bandit_pass/bandit14 拿到進入localhost的密碼
拿到之後用telnet指令連線到127.0.0.1就可以拿到密碼

Level15

Level Goal

The password for the next level can be retrieved by submitting the password of the current level to port 30001 on localhost using SSL encryption.

Helpful note: Getting “HEARTBEATING” and “Read R BLOCK”? Use -ign_eof and read the “CONNECTED COMMANDS” section in the manpage. Next to ‘R’ and ‘Q’, the ‘B’ command also works in this version of that command…

解答

用openssl s_client -connect ip:port連線後輸入lv14的密碼

Level16

Level Goal

The credentials for the next level can be retrieved by submitting the password of the current level to a port on localhost in the range 31000 to 32000. First find out which of these ports have a server listening on them. Then find out which of those speak SSL and which don’t. There is only 1 server that will give the next credentials, the others will simply send back to you whatever you send to it.

解答

用nmap -sV 127.0.0.1 -p 31000-32000搜尋127.0.0.1 port 31000~32000的通訊埠
連線那兩個ssl的通訊埠
連線到正確的通訊埠後輸入上一題的密碼會得到一串金鑰
再用lv13的方式登入下一題

Level17

Level Goal

There are 2 files in the homedirectory: passwords.old and passwords.new. The password for the next level is in passwords.new and is the only line that has been changed between passwords.old and passwords.new

NOTE: if you have solved this level and see ‘Byebye!’ when trying to log into bandit18, this is related to the next level, bandit19

解答

用diff -y 檔案1 檔案2比較兩個檔案不一樣的字串
有 | 標記的是不一樣的
按題目取password.new 中的密碼

Level18

Level Goal

The password for the next level is stored in a file readme in the homedirectory. Unfortunately, someone has modified .bashrc to log you out when you log in with SSH.

解答

先試著登入後發現會被踢出
照題目用ssh帶一個指令,打開readmessh bandit18@bandit.labs.overthewire.org -p 2220 cat readme

Level19

Level Goal

To gain access to the next level, you should use the setuid binary in the homedirectory. Execute it without arguments to find out how to use it. The password for this level can be found in the usual place (/etc/bandit_pass), after you have used the setuid binary.

解答

先用ls -l bandit20-do看檔案權限跟可執行的使用者
打開檔案後按照提示用bandit20執行
在按照題目提示從/etc/bandit_pass拿bandit20的密碼

Level20

Level Goal

There is a setuid binary in the homedirectory that does the following: it makes a connection to localhost on the port you specify as a commandline argument. It then reads a line of text from the connection and compares it to the password in the previous level (bandit20). If the password is correct, it will transmit the password for the next level (bandit21).

NOTE: Try connecting to your own network daemon to see if it works as you think

解答

用echo輸出lv20的密碼後面用netcat -lp port開起接聽模式
再用jobs查看正在執行的程式
在打開suconnect就可以得到密碼

Level21

Level Goal

A program is running automatically at regular intervals from cron, the time-based job scheduler. Look in /etc/cron.d/ for the configuration and see what command is being executed.

解答

按照題目給的路徑並打開bandit22_root
在按照檔案給的路徑走到cronjob_bandit22.sh
在按照裡面的路徑就可以得到密碼

Level22

Level Goal

A program is running automatically at regular intervals from cron, the time-based job scheduler. Look in /etc/cron.d/ for the configuration and see what command is being executed.

NOTE: Looking at shell scripts written by other people is a very useful skill. The script for this level is intentionally made easy to read. If you are having problems understanding what it does, try executing it to see the debug information it prints.

解答

按照題目給的路徑並打開bandit23
在按照檔案給的路徑走到cronjob_bandit23.sh
在按照檔案裡的程式碼執行wcho I am bandit23 | md5sum | cut -d ' ' -f 1
得到$mytarget後cat /tmp/mytarget就可以得到密碼

Level23

Level Goal

A program is running automatically at regular intervals from cron, the time-based job scheduler. Look in /etc/cron.d/ for the configuration and see what command is being executed.

NOTE: This level requires you to create your own first shell-script. This is a very big step and you should be proud of yourself when you beat this level!

NOTE 2: Keep in mind that your shell script is removed once executed, so you may want to keep a copy around…

解答

按照題目給的路徑並打開bandit24
在按照檔案給的路徑走到cronjob_bandit24.sh
打開腳本後看到第三行說會執行並刪除所有在/var/spool/$myname/foo內的sh檔
到/tmp 目錄下再創一個目錄
在目錄中開一個sh檔
腳本內的指令會將/etc/bandit_pass/bandit24複製到剛創的目錄bandit24中
腳本寫完後用touch更改系統時間
寫完腳本後分別將bandit_24.sh和bandit_pass.txt提權
提權之後ls -al確認時間
再用cp bandit_24.sh 把腳本複製到/var/spool/bandit24/foo
複製之後再ls -al確認時間
然後打開bandit_pass.txt就可以拿到密碼了

Level24

Level Goal

A daemon is listening on port 30002 and will give you the password for bandit25 if given the password for bandit24 and a secret numeric 4-digit pincode. There is no way to retrieve the pincode except by going through all of the 10000 combinations, called brute-forcing.
You do not need to create new connections each time

解答

要用24題密碼搭配一個四位數子才能拿到25題密碼而且有時間限制


for i in {0000..9999}; do echo VAfGXJ1PBSsPSnvsjI8p759leLZ9GGar $i; done | nc localhost 30002 | grep -v Wrong!

用for迴圈從0000~9999搭配密碼輸出並不輸出錯誤答案

Level25

Level Goal

Logging in to bandit26 from bandit25 should be fairly easy… The shell for user bandit26 is not /bin/bash, but something else. Find out what it is, how it works and how to break out of it.

解答

先ls看到bandit26.sshkey
用bandit26.sshkey登入會被關掉
再用cat /etc/passwd | grep bandit26看使用者資訊
發現他是用showtxt連線，要把它改成bash
用more的顯示特性把視窗縮小不讓它顯示全部
按v切到vim模式下指令:set shell=/bin/bash
再下:shell

Level26

Level Goal

Good job getting a shell! Now hurry and grab the password for bandit27!

解答

先ls看到bandit27-do
用file bandit27-do看到bandit27-do是執行檔
再用./bandit27-do執行bandit27-do
發現他會更改使用者
用./bandit27-do cat /etc/bandit_pass/bandit27直接看bandit27密碼

Level27

Level Goal

There is a git repository at ssh://bandit27-git@localhost/home/bandit27-git/repo via the port 2220. The password for the user bandit27-git is the same as for the user bandit27.

Clone the repository and find the password for the next level.

解答

先下git clone ssh://bandit27-git@localhost:2220/home/bandit27-git/repo
發現權限不夠，mktemp -d創建暫時目錄
進到目錄後再下一次git clone ssh://bandit27-git@localhost2220/home/bandit27-git/repo
進到repo目錄後cat README就可以拿到密碼

Level28

Level Goal

There is a git repository at ssh://bandit28-git@localhost/home/bandit28-git/repo via the port 2220. The password for the user bandit28-git is the same as for the user bandit28.

Clone the repository and find the password for the next level.

解答

先下git clone ssh://bandit28-git@localhost:2220/home/bandit28-git/repo
發現權限不夠，mktemp -d創建暫時目錄
進到目錄後再下一次git clone ssh://bandit28-git@localhost2220/home/bandit28-git/repo
進到repo目錄後cat README.md發現密碼被修改過

# Bandit Notes
Some notes for level29 of bandit.

## credentials

- username: bandit29
- password: xxxxxxxxxx

git log查看檔案修改紀錄
git show 899ba88df296331cc01f30d022c006775d467f28看最近一次修復訊息洩漏(fix info leak)

Level29

Level Goal

There is a git repository at ssh://bandit28-git@localhost/home/bandit28-git/repo via the port 2220. The password for the user bandit28-git is the same as for the user bandit28.

Clone the repository and find the password for the next level.

解答

先下git clone ssh://bandit29-git@localhost:2220/home/bandit29-git/repo
發現權限不夠，mktemp -d創建暫時目錄
進到目錄後再下一次git clone ssh://bandit29-git@localhost2220/home/bandit29-git/repo
進到repo目錄後cat README.md發現密碼沒在這

# Bandit Notes
Some notes for bandit30 of bandit.

## credentials

- username: bandit30
- password: <no passwords in production!>

用git branch -a查看其他分支
git checkout dev查看dev分支
打開RREADME.md發現密碼再裡面

Level30

Level Goal

There is a git repository at ssh://bandit28-git@localhost/home/bandit28-git/repo via the port 2220. The password for the user bandit28-git is the same as for the user bandit28.

Clone the repository and find the password for the next level.

解答

先下git clone ssh://bandit30-git@localhost:2220/home/bandit30-git/repo
發現權限不夠，mktemp -d創建暫時目錄
進到目錄後再下一次git clone ssh://bandit30-git@localhost2220/home/bandit30-git/repo
進到repo目錄後cat README.md發現密碼沒在這
用git tag查看標籤
git show secret查看secret標籤，發現密碼再裡面

Level31

Level Goal

There is a git repository at ssh://bandit28-git@localhost/home/bandit28-git/repo via the port 2220. The password for the user bandit28-git is the same as for the user bandit28.

Clone the repository and find the password for the next level.

解答

先下git clone ssh://bandit31-git@localhost:2220/home/bandit31-git/repo
發現權限不夠，mktemp -d創建暫時目錄
進到目錄後再下一次git clone ssh://bandit31-git@localhost2220/home/bandit31-git/repo
進到repo目錄後cat README.md發現密碼沒在這

This time your task is to push a file to the remote repository.

Details:
    File name: key.txt
    Content: 'May I come in?'
    Branch: master

打開gitignore，發現他不會記錄txt檔
再依照題目條件建檔，先把檔案從工作區add到暫存區，這裡-f是要強制加入，再把檔案push到遠端
push後密碼就出來了

Level32

Level Goal

After all this git stuff its time for another escape. Good luck!

解答

先下ls發現指令變大寫
$0引用shell
出來後下ls /etc/bandit_pass/bandit33取密碼

心得

OverTheWire - Bandit是我第一次解完一整系列的CTF題目，從0基礎開始研究linux指令，一開始還是會有指令記不住之類的問題，但打久後自然就記起來了，題目都是全英文的，下方都有附相關指令的用法。花了六周解完這系列題目有助於我對linux指令更進一步了解。

Syntax	Example	Reference
# Header	Header	基本排版
- Unordered List	Unordered List
1. Ordered List	Ordered List
- [ ] Todo List	Todo List
> Blockquote	Blockquote
Bold font	Bold font
Italics font	Italics font
~~Strikethrough~~	~~Strikethrough~~
19^th^	19^th
H~2~O	H₂O
++Inserted text++	Inserted text
==Marked text==	Marked text
[link text](https:// "title")	Link
![image alt](https:// "title")	Image
`Code`	`Code`	在筆記中貼入程式碼
```javascript var i = 0; ```	`var i = 0;`	在筆記中貼入程式碼
:smile:		Emoji list
{%youtube youtube_id %}	Externals
$L^aT_eX$	L^aT_eX
:::info This is a alert area. :::	This is a alert area.