Questions tagged [ctf]

Capture the Flag (CTF) is a form of hacking competition. Use for questions about the design and operation of such contests. Do not use for questions asking for help with winning contests.

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83 views

Hacker101 Spoilter #2 EASY Micro-CMS v1

I am just getting into CTF and Hacking in general. I am very confused as to why this worked when I added an apostrophe to the end it reveals the flag. I have Burp Community Edition suite going and I ...
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0answers
4 views

Best practise to create virtual networks for CTF [migrated]

I've build a CTF server at home for me and my friends. By CTF server I mean a pretty decent server with quite OK specs on which XenServer (free version) is running, I download and mount a VM from ...
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1answer
47 views

Extract data from burp response and use in another request

I have a scenario where I need to call /api/login to get a token and then use said token in subsequent calls until it expires. Is there a way to automate the call and token extraction and then to ...
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1answer
91 views

Protect server in CTF challenge when exploting input() vulnerability in python

There was this challenge in one of the CTF's I played in which you had to exploit the input vulnerability of Python 2.x . I was just wondering that since the input function in Python 2.x is same as ...
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0answers
100 views

How to produce remote code execution via pickling an object

I'm working on a challenge that was presented to me without much prior knowledge of Python and the pickle library. I'm unable to post the challenge's code for reasons. In short though I am accessing ...
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2answers
246 views

Understanding SQLMAP payload

I was participating in a CTF and there was a SQL Injection challenge. There is a Wordpress page with a vulnerable plugin parameter (let's call the website https://vulnerable.com/), and the solution ...
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2answers
135 views

Pickle Shellcode Import Error

I'm trying to execute pickle shell-code through a download function on a website but I get the following error: <html> <h1>ERROR: Cannot load file</h1> <!-- Traceback (most ...
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1answer
206 views

How to use Nmap as a port knocking client?

I want to use Nmap for port knocking on CTF machines, so I've read the manual for configuring it properly: nmap <ip> -p <port1>,<port2>,... -r --max-retries 0 --max-parallelism 1 ...
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0answers
106 views

Meterpreter Upload won't work

I am trying to follow a walkthrough for a CTF and there is one point where i have to upload a unix-privesc-check file to the other machine. Well when i use the command i get this response upload /...
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1answer
2k views

Is there a way to exploit jquery 1.12.4 vulnerability?

According to https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=jquery+1.12.4 and https://snyk.io/test/npm/jquery/1.12.4, I see that jQuery 1.12.4 has medium serevrity vulnerability. I checked on ...
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0answers
74 views

Help needed in identifying a string [closed]

I need help in identifying the following string in order to decode it to a piece of meaningful information. h_t_s_/_g_s_._k_l_b_c_m_4_9_a_k_6_f_8_4_8_e_e_r_9_3_9_f_
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0answers
41 views

Need help in finding flags in secret files [duplicate]

Need help in identifying or decrypting strings to find flags in capture the flag competitions. Please provide any guides or help.
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1answer
251 views

Risk involved with using SSH for CTF challenges? [duplicate]

I'm new to the INFOSEC scene and was intrigued by the concept of CTF challenges. I was hoping to get started with OverTheWire.org which requires you to SSH to their server to complete the challenges. ...
2
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0answers
67 views

Shellcode different on guide

I followed a guide to do narnia2 of overthewire and the shellcode generated by them was: h\x01\x01\x01\x01\x814$ri\x01\x011\xd2Rj\x04Z\x01\xe2R\x89\xe2jhh///sh/binj\x0bX\x89\xe3\x89\xd1\x99\xcd\x80 ...
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5answers
22k views

What exactly is CTF and how can I as programmer prepare for a CTF with beginner-friendly people?

I reached out to an old friend of mine who was a terrific programmer back in my school days and he invited me to attend one of the CTF events with his university group. This group seems very beginner ...
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3answers
255 views

Difference between phpp, php, and phP? [closed]

I came across a ctf challenge where php file upload was restricted but phpp and phP were not. What other formats can php be uploaded in and what is the difference?
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2answers
122 views

Buffer Overflow problem [closed]

I have a quick question about a buffer-overflow exploit in a 64-bit binary. Lately, I have found some basic buffer overflow vulnerabilities. I hoped I knew how to manage it, but apparently, I don't. ...
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2answers
788 views

Shellcode does not execute as the owner

(This is a question regarding a challenge in a wargame on overthewire.org called Narnia) Here is the source code of the vulnerable script "narnia1" I intend to exploit: #include <stdio.h> int ...
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0answers
48 views

Function epilogue behavior since GCC 4.9.0

I'll use the following C code to explain my question: #include <stdio.h> int main(void) { printf("foo\n"); return 0; } Before GCC 4.9.0, disassemblying it produces: .LC0: .string ...
1
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1answer
224 views

zap proxy - modify post to inject a zip file

I am doing a CTF image now, and I need to upload a .zip file to execute using the php wrapper zip:// using this PHP ZIP Wrapper LFI vulnerability The problem is that the only way to upload is with ...
3
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1answer
3k views

How to use a sh SUID script to get privilege escalation?

As www-data user (non-privileged user) I have found this SUID, world-writable shell script: www-data@Cisco:/home/cripto$ ls -al /etc/init.d/admin -rwsr-xrwx 1 root bob 233 Nov 12 13:09 /etc/init.d/...
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1answer
2k views

SQL Injection - LIKE Clause

As part of a capture-the-flag assignment, I'm supposed to perform SQL injection using the LIKE clause to obtain the flag. I'm new to this and I've tried the following injections: (The username ...
2
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1answer
5k views

How to find a wep key inside a pcap file with only 2 IV?

I have a pcap file that contains 3 packets. I need to find a WEP key inside these packets. These packets contains only two IV. It's not a live attack so I can't try brute force.
0
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1answer
397 views

How exploitable is a QR code in a login system?

I'm taking a CTF challenge on a web service. The goal is to gather the most information possible of a user. I have access to it's login and password, but password is expired and the account must be ...
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1answer
4k views

Overwriting return address of main function

I am new to CTFs and I was asked to solve this: #include <cstdio> // g++ pwn2.cpp -o pwn2 -static void ilocamp() { char flaga[1024] = {0}; FILE *f = fopen("flag2.txt", "r"); ...
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1answer
342 views

Help choosing the right virtualization for a CTF [closed]

I am a High School cyber computer science teacher who also teaches courses on cyber security. I have been looking around for some good 'beginner' CTFs that I could organize for my students, but ...
3
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1answer
114 views

Are there any academic papers/books about hacking wargames?

I'm looking for sources (academic papers, books, articles from notable magazines) that can be used as reference for a Bachelor's Thesis, that should be about making an educational, gamified hacking ...
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4answers
3k views

Reduce Noise when Penetration Testing

Recently I participated in a capture the flag competition which was attached with SOC analysis teams monitoring our traffic. There we were told that many tools were very noisy. Eg Sqlmap which has ...
0
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1answer
451 views

From a local file inclusion to a shell when file is downloaded?

I've just participated in a boot2root capture the flag event where I got close to solving an item but couldn't quite get it over the line and want to learn what I could have done differently. In the ...
2
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1answer
210 views

Looking for a race condition example that we can use internally in training

I'm making a small CTF for my digital team to teach them about different exploits. I'm hoping to include a race condition example but everything I've found manipulates a local file or SQL database (so ...
3
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1answer
153 views

Ctf creation sandboxed question

I have a tiny question, we are creating a ctf but we stumbled upoun a idea that we don't know how to solve. As several websites that create ctf's as hack.me use sandboxes. Due to the security and ...
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0answers
345 views

kernel panic after exploiting dirty cow on kernel 3.13.0

After exploiting the dirty cow vulnerabillity https://www.exploit-db.com/exploits/40839/ my ubuntu virtual machine keep getting a kernel panic after every reboot. What could possibly cause this ...
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0answers
73 views

CSAW 2012 challenge2 can't get shell out side of gdb

I tried to solve this problem. I found FSB at 0x08048bfe _snprintf. I loaded shell code by \n. ssc function checks whether user input include /bin/sh. Most of shell code includes /bin/sh. I found ...
15
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1answer
3k views

Steganography - JPEGsnoop

I am trying to overcome a CTF steganography challenge. I tried different methods to unhide the hidden data in the file without luck. I used JPEGsnoop on the image and I got this output: *** Decoding ...
15
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4answers
5k views

How to build a hacking challenge that uses XSS?

Security conferences often have hacking challenges. My colleagues and I have built a number of these. We've not yet done one that includes a cross-site scripting vulnerability. I have seen challenges ...
0
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1answer
656 views

Is there a good site I can use to convert a string into any encoding? [closed]

I am working on a ctf (capture the flag) challenge and I have a string that I believe is important, but I don't know what encoding it is in. Is there a way I can decode the string in all of the ...
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3answers
2k views

Looking for some steganography guidance

I am currently trying to figure out a steganography challenge. I was given 3 images, a secret.txt file and a "binary" file. There are no instructions as this was part of another challenge. I am ...
0
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1answer
196 views

LFI Why would I not see a response

I have the below two vulnerable PHP code sections in 2 files. I found the sources of these in an anony access FTP backup file home.tar.gz. So I'm getting the content of /etc/passwd with the null byte ...
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1answer
518 views

Did DARPA's Cyber Grand Challenge winner actually discover previously unknown vulnerabilities?

DARPA announced a winner on August 4, 2016 of its Cyber Grand Challenge DARPA Cyber Grand Challenge. The contest was described as designed to accelerate the development of advanced, autonomous ...
4
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1answer
1k views

Exploiting MD5/Salt Vulnerability in this PHP form?

I've been practicing security-related subjects and this challenge has befuddled me. Note: I can't access any PHP source code, nor can I edit it. I'm only able to view it. The following is given: I ...
4
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3answers
570 views

Is this PHP code vulnerable SQL injection?

Im given control over the $vote variable (in the "challenge" function) Is there any way to sql inject the query? (BTW I can see/read whatever the challenge function returns e.g. the sql errors. I ...
7
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1answer
3k views

PHP Session Vulnerability

I'm trying to solve a challenge on a CTF, with PHP sessions. The goal is to make check.php echo $_PASSWORD. I do not have access to the files themselves, and therefore I cannot edit them. My ...
2
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2answers
875 views

How to decrypt text when four first letters of the key are missing in Facebook CTF contest?

I am beginner in cyber security. Now I am participating on Facebook Catch the Flag contest. I have to solve following task: There is a key. But the first four characters of the key are missing: _ _ ...
2
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1answer
6k views

How to bypass PHP username and password check in this CTF challenge?

I'm preparing for this CTF challenge I'll be participating in next week, and I ran across this problem online which I can't manage to solve. I only have control of the variables $user and $pass that ...
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1answer
2k views

Any CTF sites besides CTF365 [closed]

I am looking for free ctf sites like ctf365, but I want a challenge and not vulnerable-by-design machines. Any references?
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0answers
1k views

Apache Web Server ETag Header Information Disclosure Weakness

How this vulnerability allow remote attackers to obtain sensitive information likes inode number and child process though ETag header ? and how to locate path to a file from inode number ?
1
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1answer
578 views

Hosting a “Capture the Flag” style competition for fun and learning? [duplicate]

A few friends and I want to run some kind of CTF competition in which we both have identical OSes that we can attack and defend as teams/individuals. I was looking on the web and I found some good ...
14
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6answers
11k views

Designing a Capture The Flag target and game management system

I've attended several CTF contests and I'd like to implement a CTF system for my students. I asked Google about designing such system but it's fruitless. Any ideas?