MISC 我的心是冰冰的
描述：似乎有信息被隱藏了。
1.首先，思路是盲猜用圖中的信息解壓縮包的密碼
另一邊用zip爆破工具爆破，節省時間，爆破居然先爆破出來了
密碼是：gnibgnib
2.然后分析bingbing.pcapng
打開后發現是usb鍵盤流量，或者是usb鼠標流量
網上查資料可得，USB協議的數據部分在Leftover Capture Data域之中，右鍵leftover capture data –> 應用為列，可以將該域的值在主面板上顯示，鍵盤數據包的數據長度為8個字節，擊鍵信息集中在第3個字節，每次key stroke都會產生一個keyboard event usb packet
可以將 leftover capture data單獨提取出來，在linux中，具體命令為：
tshark -r bingbing.pcap -T fields -e usb.capdata > usbdata.txt
因此，這就是usb鍵盤流量
3.從得出的userdata.txt文件中過濾出鍵盤擊鍵相關的流量，並根據映射表，將鍵盤按鍵按照對應關系輸出出來，查資料找到了網上的腳本
1 #!/usr/bin/env python 2 3 import sys 4 5 import os 6 7 8 9 DataFileName = "usbdata.txt" 10 11 12 13 presses = [] 14 15 16 17 normalKeys = {"04":"a", "05":"b", "06":"c", "07":"d", "08":"e", "09":"f", "0a":"g", "0b":"h", "0c":"i", "0d":"j", "0e":"k", "0f":"l", "10":"m", "11":"n", "12":"o", "13":"p", "14":"q", "15":"r", "16":"s", "17":"t", "18":"u", "19":"v", "1a":"w", "1b":"x", "1c":"y", "1d":"z","1e":"1", "1f":"2", "20":"3", "21":"4", "22":"5", "23":"6","24":"7","25":"8","26":"9","27":"0","28":"<RET>","29":"<ESC>","2a":"<DEL>", "2b":"\t","2c":"<SPACE>","2d":"-","2e":"=","2f":"[","30":"]","31":"\\","32":"<NON>","33":";","34":"'","35":"<GA>","36":",","37":".","38":"/","39":"<CAP>","3a":"<F1>","3b":"<F2>", "3c":"<F3>","3d":"<F4>","3e":"<F5>","3f":"<F6>","40":"<F7>","41":"<F8>","42":"<F9>","43":"<F10>","44":"<F11>","45":"<F12>"} 18 19 20 21 shiftKeys = {"04":"A", "05":"B", "06":"C", "07":"D", "08":"E", "09":"F", "0a":"G", "0b":"H", "0c":"I", "0d":"J", "0e":"K", "0f":"L", "10":"M", "11":"N", "12":"O", "13":"P", "14":"Q", "15":"R", "16":"S", "17":"T", "18":"U", "19":"V", "1a":"W", "1b":"X", "1c":"Y", "1d":"Z","1e":"!", "1f":"@", "20":"#", "21":"$", "22":"%", "23":"^","24":"&","25":"*","26":"(","27":")","28":"<RET>","29":"<ESC>","2a":"<DEL>", "2b":"\t","2c":"<SPACE>","2d":"_","2e":"+","2f":"{","30":"}","31":"|","32":"<NON>","33":"\"","34":":","35":"<GA>","36":"<","37":">","38":"?","39":"<CAP>","3a":"<F1>","3b":"<F2>", "3c":"<F3>","3d":"<F4>","3e":"<F5>","3f":"<F6>","40":"<F7>","41":"<F8>","42":"<F9>","43":"<F10>","44":"<F11>","45":"<F12>"} 22 23 24 25 def main(): 26 27 # check argv 28 29 if len(sys.argv) != 2: 30 31 print "Usage : " 32 33 print " python UsbKeyboardHacker.py data.pcap" 34 35 print "Tips : " 36 37 print " To use this python script , you must install the tshark first." 38 39 print " You can use `sudo apt-get install tshark` to install it" 40 41 print "Author : " 42 43 print " Angel_Kitty <angelkitty6698@gmail.com>" 44 45 print " If you have any questions , please contact me by email." 46 47 print " Thank you for using." 48 49 exit(1) 50 51 52 53 # get argv 54 55 pcapFilePath = sys.argv[1] 56 57 58 59 # get data of pcap 60 61 os.system("tshark -r %s -T fields -e usb.capdata > %s" % (pcapFilePath, DataFileName)) 62 63 64 65 # read data 66 67 with open(DataFileName, "r") as f: 68 69 for line in f: 70 71 presses.append(line[0:-1]) 72 73 # handle 74 75 result = "" 76 77 for press in presses: 78 79 Bytes = press.split(":") 80 81 if Bytes[0] == "00": 82 83 if Bytes[2] != "00": 84 85 result += normalKeys[Bytes[2]] 86 87 elif Bytes[0] == "20": # shift key is pressed. 88 89 if Bytes[2] != "00": 90 91 result += shiftKeys[Bytes[2]] 92 93 else: 94 95 print "[-] Unknow Key : %s" % (Bytes[0]) 96 97 print "[+] Found : %s" % (result) 98 99 100 101 # clean the temp data 102 103 os.system("rm ./%s" % (DataFileName)) 104 105 106 107 108 109 if __name__ == "__main__": 110 111 main()
最后結果從<DEL>分段分別解密文， 16進制解碼即可
flag值： flag{8f9ed2f933ef14a8d0523d0349e1299c}
總結：挺有勁兒的一題，做了好久，明明答案早已經出來了，開始卻沒發現那是16進制，輾轉了好久，以為是腳本錯了，折騰好久，最后才想到答案可能是密文，提交答案時卻是第10名提交的，錯失前三血
MISC 簽到
答對8道數據安全知識小競賽題，得flag
flag值： flag{7e63095d-4310-4f24-a01a-4a858d442fab}
賽后感受：題目好多不會做，還是很自閉了，感謝隊友的輔助，一起加油！