반응형 CTF9 Basic password cracking (MD5, SHA1, ..) 기본적인 password cracking과 같은 문제를 CTF에서는 종종 접할 수 있다. 과거에도 비슷한 코드를 작성했었지만 메모리 초과로 인해서 포기하곤 했는데 우연히 검색을 하다가 알게된 부분이 있어서 공유해보고자 한다. 기본적으로 - MD5 : 32-bit hex digits - SHA1 : 40-bit hex digits - SHA256 : 256-bit hex digits 우선, 일부 문자열은 제공되어 있고 숫자만 padding하여 해쉬 값을 계산하는 것은 아래와 같다. 예제에서 주어진 것 처럼 실제 0000부터 9999까지 숫자만 붙여서 주어진 hash 값을 비교하는 것이므로 해당 예제는 상당히 간단하다. import hashlib prefix = "CTF-TEST-" match = "bf9e.. 2020. 7. 2. Chaos Communication Camp 2019 (Ancient Data) Ancient Data Category: Misc Difficulty: Easy (Google the world) Author: TheVamp That is some ancient stuff! Could you translate that for us? Put your translated text in the following format, to submit the Flag: ALLES{} ***** I simply googled keyword by ancient letters and then I got the following image as below. Afterward, it is just a piece of cake. So, the flag is ALLES{ALPHABETEVOLUTION} Refe.. 2019. 8. 28. Securinets Prequals 2K19 Write-up (Easy Trade) This is a basic forensic question. This is my approach. I only used Wireshark Follow TCP Stream feature. Fortunately, the provided pcap file is not big so I skimmed every line. In the pcap file I found some clues for the flag. Between hosts exchanged the key and flag.txt is sent in a zip file. >> 50 40 03 04 is the signature for zip file I used the Follow TCP Stream function (Analyze >> Follow >.. 2019. 3. 24. TAMUctf '19 Write-up (I heard you like files) As we open the uploaded file, we can see below image. After I downloaded this file, I checked the hidden file itself by binwalk command. $ binwalk art.png DECIMAL HEXADECIMAL DESCRIPTION--------------------------------------------------------------------------------0 0x0 PNG image, 1920 x 1080, 8-bit/color RGBA, non-interlaced3408641 0x340301 PDF document, version: "1.5"3408712 0x340348 Zlib com.. 2019. 3. 24. 이전 1 2 3 다음 반응형
