流量分析

USB流量

工具:knm

键盘流量

USB协议数据部分在Leftover Capture Data域中,数据长度为八个字节。其中键盘击键信息集中在第三个字节中。键位映射关系参考:《USB键盘协议中键码》中的HID Usage ID

步骤

  1. tshark命令提取cap data

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

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

  2. 将数据还原成键位

    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]

    加冒号:

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    f=open('usbdata.txt','r')
    fi=open('out.txt','w')
    while 1:
    a=f.readline().strip()
    if a:
    if len(a)==16:
    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()

    还原键位:

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    #python2
    #脚本1
    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
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    #python3
    #脚本2
    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))

鼠标流量

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0x00时代表没有按键,为0x01时代表按左键,为0x02时代表按右键。

第二个字节可以看成是一个signed byte类型,其最高位为符号位,当这个值为正时,代表鼠标水平右移多少像素,为负时,代表水平左移多少像素。

第三个字节与第二字节类似,代表垂直上下移动的偏移。

步骤

  1. tshark命令提取cap data

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

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

  2. 将鼠标数据还原鼠标移动轨迹

    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]

    加冒号:

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    f=open('usbdata.txt','r')
    fi=open('out.txt','w')
    while 1:
    a=f.readline().strip()
    if a:
    if len(a)==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()
  3. 测试信息隐藏位置

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    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()
  4. gnuplot将坐标转化成图像

    gnuplot

    gnuplot> plot "xy.txt"

  • TLS流量

    解密:Wireshark首选项 - TLS - RSA keys list - Edit… - TLS Decrypt