USB流量分析

最新推荐文章于 2025-03-07 17:57:27 发布

Atkxor

最新推荐文章于 2025-03-07 17:57:27 发布

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分类专栏： CTF 文章标签： wireshark usb

本文链接：https://blog.youkuaiyun.com/qq_46150940/article/details/115431953

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本文详细介绍了如何解析USB鼠标和键盘流量数据，用于CTF竞赛中的信息隐藏。通过Python脚本，从Wireshark捕获的流量包中提取鼠标和键盘的移动轨迹及按键信息，并转换为坐标或字符。实战练习中，展示了不同脚本的使用，以及如何将流量数据转化为可读的字符串，最终揭示隐藏的flag。

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目录标题

鼠标流量

基础知识

USB协议鼠标数据部分在Leftover Capture Data域中，数据长度为四个字节

第一个字节,代表按键

当取0×00时,代表没有按键
当取0×01时,代表按左键
当取0×02时,代表当前按键为右键

第二个字节,可看作为signed byte类型，其最高位为符号位，

当值为正时，代表鼠标右移像素位；
值为负时，代表鼠标左移像素位。

第三个字节,代表垂直上下移动的偏移。

当值为正时，代表鼠标上移像素位；
值为负时，代表鼠标下移像素位。

实战练习

flag隐藏在usb流量中，通过USB协议数据中的鼠标移动轨迹转换成flag

题目
方法1：
基于python2的UsbMiceHacker.py脚本

#!/usr/bin/env python
# coding:utf-8

import sys
import os
import numpy as np
import matplotlib.pyplot as plt

mousePositionX = 0
mousePositionY = 0

X = []
Y = []

DataFileName = "usb.dat"
data = []

def main():
    global mousePositionX
    global mousePositionY
    # check argv
    if len(sys.argv) != 3:
        print "Usage : "
        print "        python UsbMiceHacker.py data.pcap [LEFT|RIGHT|MOVE|ALL]"
        print "Tips : "
        print "        To use this python script , you must install the numpy,matplotlib first."
        print "        You can use `sudo pip install matplotlib numpy` to install it"
        print "Author : "
        print "        WangYihang <wangyihanger@gmail.com>"
        print "        If you have any questions , please contact me by email."
        print "        Thank you for using."
        exit(1)

    # get argv
    pcapFilePath = sys.argv[1]
    action = sys.argv[2]

    if action != "LEFT" and action != "ALL" and action != "RIGHT" and action != "MOVE":
        action = "LEFT"

    # get data of pcap
    command = "tshark -r '%s' -T fields -e usb.capdata > %s" % (
        pcapFilePath, DataFileName)
    print command
    os.system(command)

    # read data
    with open(DataFileName, "r") as f:
        for line in f:
            data.append(line[0:-1])

    # handle move
    for i in data:
        Bytes = i.split(":")
        if len(Bytes) == 8:
            horizontal = 2  # -
            vertical = 4  # |
        elif len(Bytes) == 4:
            horizontal = 1  # -
            vertical = 2  # |
        else:
            continue
        offsetX = int(Bytes[horizontal], 16)
        offsetY = int(Bytes[vertical], 16)
        if offsetX > 127:
            offsetX -= 256
        if offsetY > 127:
            offsetY -= 256
        mousePositionX += offsetX
        mousePositionY += offsetY
        if Bytes[0] == "01":
            # print "[+] Left butten."
            if action == "LEFT":
                # draw point to the image panel
                X.append(mousePositionX)
                Y.append(-mousePositionY)
        elif Bytes[0] == "02":
            # print "[+] Right Butten."
            if action == "RIGHT":
                # draw point to the image panel
                X.append(mousePositionX)
                Y.append(-mousePositionY)
        elif Bytes[0] == "00":
            # print "[+] Move."
            if action == "MOVE":
                # draw point to the image panel
                X.append(mousePositionX)
                Y.append(-mousePositionY)
        else:
            # print "[-] Known operate."
            pass
        if action == "ALL":
            # draw point to the image panel
            X.append(mousePositionX)
            Y.append(-mousePositionY)

    fig = plt.figure()
    ax1 = fig.add_subplot(111)

    ax1.set_title('[%s]-[%s] Author : WangYihang' % (pcapFilePath, action))
    ax1.scatter(X, Y, c='r', marker='o')
    plt.show()

    # clean temp data
    os.system("rm ./%s" % (DataFileName))

if __name__ == "__main__":
    main()

还有基于python3的UsbMiceDataHacker.py脚本

python3 UsbMiceDataHacker.py usb2.pcap RIGHT
#RIGHT代表右键

我这里什么也没有
在这里插入图片描述
贴上其他人成功的结果

方法2：
提取鼠标流量数据

tshark -r usb2.pcap -T fields -e usb.capdata > usbdata.txt

查看usbdata.txt
在这里插入图片描述
剔除空行，亲身经历，这步很重要，包含空行会得到错误结果

tshark -r usb2.pcap -T fields -e usb.capdata | sed '/^\s*$/d' > usbdata.txt

没有冒号，使用脚本添加冒号

f=open('usbdata.txt','r')
fi=open('out.txt','w')
while 1:
    a=f.readline().strip()
    if a:
        if len(a)==8: # 键盘流量len=16，鼠标流量len=8
            out=''
            for i in range(0,len(a),2):
                if i+2 != len(a):
                    out+=a[i]+a[i+1]+":"
                else:
                    out+=a[i]+a[i+1]
            fi.write(out)
            fi.write('\n')
    else:
        break

fi.close()

运行脚本，得到out.txt
在这里插入图片描述
使用mouse.py脚本，通过更改btn_flag的值来测试鼠标左右键

nums = []
keys = open('out.txt','r')
f = open('xy.txt','w')
posx = 0
posy = 0
for line in keys:
    if len(line) != 12 :
        continue
    x = int(line[3:5],16)
    y = int(line[6:8],16)
    if x > 127 :
        x -= 256
    if y > 127 :
        y -= 256
    posx += x
    posy += y
    btn_flag = int(line[0:2],16)  # 1 for left , 2 for right , 0 for nothing
    if btn_flag == 2 : # 1 代表左键
        f.write(str(posx))
        f.write(' ')
        f.write(str(posy))
        f.write('\n')

f.close()

经过测试是鼠标右键流量，在生成的xy.txt中可以得到坐标：
在这里插入图片描述

看了大师傅的wp，发现我们添加冒号得到的内容不一样

在这里插入图片描述

大师傅直接提取鼠标流量，含有冒号，而我提取出来的不含冒号，是Wireshark版本不同的缘故，在网上找到老版本的Wireshark

Wireshark-win64-2.4.3
https://pan.baidu.com/s/1nvIIKpr
密码：5uao

提取流量得到usbdata.txt,包含冒号：在这里插入图片描述
直接使用上面的mouse.py脚本，即可得到xy.txt。

进入gnuplot工具，把xy.txt文本里的坐标转化为图片

翻转一下图片

得到flag

XNCA{U2BPCAPCETEVERYTHING}

也可以利用python脚本画图

import matplotlib.pyplot as plt
import numpy as np

x, y = np.loadtxt('xy.txt', delimiter=' ', unpack=True)
plt.plot(x, y, '.')
plt.show()

得到
在这里插入图片描述

键盘流量

基础知识

USB协议数据部分在Leftover Capture Data域中，数据长度为八个字节。

击键信息集中在第3个字节，每次击键都会产生一个数据包。

参考文档：USB keyboard映射表
在这里插入图片描述

实战练习

flag信息一般隐藏在USB流量中，通过USB协议数据中的键盘键码转换成键位。

题目1：
分析流量包，发现数据是16位，所以是USB键盘流量
在这里插入图片描述
tshark提取USB流量

tshark -r bingbing.pcapng -T fields -e usb.capdata > usbdata.txt

usbdata.txt文件内容
在这里插入图片描述
发现提取出来包含空行，使用命令剔除空行

tshark -r bingbing.pcapng -T fields -e usb.capdata | sed '/^\s*$/d' > usbdata.txt

查看usbdata.txt空余行消失
在这里插入图片描述
提取出来的数据可能会带冒号，也可能不带，但是一般的脚本都会按照有冒号的数据来识别。有冒号时提取数据的[6:8]，无冒号时数据在[4:6]

可以利用脚本加上冒号

f=open('usbdata.txt','r')
fi=open('out.txt','w')
while 1:
    a=f.readline().strip()
    if a:
        if len(a)==16: # 键盘流量len=16，鼠标流量len=8
            out=''
            for i in range(0,len(a),2):
                if i+2 != len(a):
                    out+=a[i]+a[i+1]+":"
                else:
                    out+=a[i]+a[i+1]
            fi.write(out)
            fi.write('\n')
    else:
        break

fi.close()

在这里插入图片描述
在网上找到两个键盘流量脚本

keyboard1.py

mappings = { 0x04:"A",  0x05:"B",  0x06:"C", 0x07:"D", 0x08:"E", 0x09:"F", 0x0A:"G",  0x0B:"H", 0x0C:"I",  0x0D:"J", 0x0E:"K", 0x0F:"L", 0x10:"M", 0x11:"N",0x12:"O",  0x13:"P", 0x14:"Q", 0x15:"R", 0x16:"S", 0x17:"T", 0x18:"U",0x19:"V", 0x1A:"W", 0x1B:"X", 0x1C:"Y", 0x1D:"Z", 0x1E:"1", 0x1F:"2", 0x20:"3", 0x21:"4", 0x22:"5",  0x23:"6", 0x24:"7", 0x25:"8", 0x26:"9", 0x27:"0", 0x28:"\n", 0x2a:"[DEL]",  0X2B:"    ", 0x2C:" ",  0x2D:"-", 0x2E:"=", 0x2F:"[",  0x30:"]",  0x31:"\\", 0x32:"~", 0x33:";",  0x34:"'", 0x36:",",  0x37:"." }

nums = []
keys = open('out.txt')
for line in keys:
    if line[0]!='0' or line[1]!='0' or line[3]!='0' or line[4]!='0' or line[9]!='0' or line[10]!='0' or line[12]!='0' or line[13]!='0' or line[15]!='0' or line[16]!='0' or line[18]!='0' or line[19]!='0' or line[21]!='0' or line[22]!='0':
         continue
    nums.append(int(line[6:8],16))

keys.close()

output = ""
for n in nums:
    if n == 0 :
        continue
    if n in mappings:
        output += mappings[n]
    else:
        output += '[unknown]'

print 'output :\n' + output

运行脚本得到：

┌──(kali㉿kali)-[~/桌面/Python/USB]
└─$ python keyboard.py                 
output :
666C61677B3866396564326639333365662[DEL]31346138643035323364303334396531323939637D

因为[DEL]是删除键，所以

666C61677B38663965643266393333656631346138643035323364303334396531323939637D

keyboard2.py

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>"}
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>"}
output = []
keys = open('out.txt')
for line in keys:
    try:
        if line[0]!='0' or (line[1]!='0' and line[1]!='2') or line[3]!='0' or line[4]!='0' or line[9]!='0' or line[10]!='0' or line[12]!='0' or line[13]!='0' or line[15]!='0' or line[16]!='0' or line[18]!='0' or line[19]!='0' or line[21]!='0' or line[22]!='0' or line[6:8]=="00":
             continue
        if line[6:8] in normalKeys.keys():
            output += [[normalKeys[line[6:8]]],[shiftKeys[line[6:8]]]][line[1]=='2']
        else:
            output += ['[unknown]']
    except:
        pass

keys.close()

flag=0
print("".join(output))
for i in range(len(output)):
    try:
        a=output.index('<DEL>')
        del output[a]
        del output[a-1]
    except:
        pass

for i in range(len(output)):
    try:
        if output[i]=="<CAP>":
            flag+=1
            output.pop(i)
            if flag==2:
                flag=0
        if flag!=0:
            output[i]=output[i].upper()
    except:
        pass

print ('output :' + "".join(output))

运行脚本得到

┌──(kali㉿kali)-[~/桌面/Python/USB]
└─$ python keyboard2.py bingbing.pcapng      
666c61677b3866396564326639333365662<DEL>31346138643035323364303334396531323939637d
output :666c61677b38663965643266393333656631346138643035323364303334396531323939637d

使用脚本将十六进制转换为字符串

m="666C61677B38663965643266393333656631346138643035323364303334396531323939637D"
s=bytes.fromhex(m)
print(s)

得到

b'flag{8f9ed2f933ef14a8d0523d0349e1299c}'

题目2：

在这里插入图片描述
提取流量

tshark -r key.pcap -T fields -e usb.capdata > usbdata.txt

查看usbdata.txt内容
在这里插入图片描述
这是找到的第三个脚本UsbKeyboardDataHacker.py

#!/usr/bin/env python3

import sys
import os

DataFileName = "usb.dat"

presses = []

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>"}

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>"}

def main():
    # check argv
    if len(sys.argv) != 2:
        print("Usage : ")
        print("        python UsbKeyboardHacker.py data.pcap")
        print("Tips : ")
        print("        To use this python script , you must install the tshark first.")
        print("        You can use `sudo apt-get install tshark` to install it")
        print("Author : ")
        print("        WangYihang <wangyihanger@gmail.com>")
        print("        If you have any questions , please contact me by email.")
        print("        Thank you for using.")
        exit(1)

    # get argv
    pcapFilePath = sys.argv[1]
    
    # get data of pcap
    os.system("tshark -r %s -T fields -e usb.capdata 'usb.data_len == 8' > %s" % (pcapFilePath, DataFileName))

    # read data
    with open(DataFileName, "r") as f:
        for line in f:
            presses.append(line[0:-1])
    # handle
    result = ""
    for press in presses:
        if press == '':
            continue
        if ':' in press:
            Bytes = press.split(":")
        else:
            Bytes = [press[i:i+2] for i in range(0, len(press), 2)]
        if Bytes[0] == "00":
            if Bytes[2] != "00" and normalKeys.get(Bytes[2]):
                result += normalKeys[Bytes[2]]
        elif int(Bytes[0],16) & 0b10 or int(Bytes[0],16) & 0b100000: # shift key is pressed.
            if Bytes[2] != "00" and normalKeys.get(Bytes[2]):
                result += shiftKeys[Bytes[2]]
        else:
            print("[-] Unknow Key : %s" % (Bytes[0]))
    print("[+] Found : %s" % (result))

    # clean the temp data
    os.system("rm ./%s" % (DataFileName))


if __name__ == "__main__":
    main()

运行脚本

└─$ python3 UsbKeyboardDataHacker.py key.pcap                                                                                        1 ⨯
[-] Unknow Key : 01
[-] Unknow Key : 01
[+] Found : aababacbbdbdccccdcdcdbbcccbcbbcbbaababaaaaaaaaaaaaaaaaaakey{xinan}

参考文章：
https://blog.youkuaiyun.com/qq_45555226/article/details/102810474
https://github.com/WangYihang/UsbMiceDataHacker
https://blog.youkuaiyun.com/qq_43431158/article/details/108717829

CTF流量分析总结题目：

https://pan.baidu.com/s/1bGEIPeXDCbhybmWOyGr8Og#list/path=%2F
提取码：q6ro