Category Archives: Useful scripts

Detect shared hosting with Bing

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Bing has a pretty cool IP advanced search operator. It can be used to detect shared hosting. It is quite annoying to type in each IP manually when you have to check several IPs (e.g. corporate IP network). The following script will scan an entire range of IPs. The examples below (Google IPs 74.125.39.103 to 74.125.39.106) give some pretty interesting results…

def printBingSharedHosting(ip_start, ip_end):
    import urllib2
    import re
    
    bing_url = 'http://www.bing.com/search?q=ip%3A'
    no_results_string = "No results"
    
    def bing_shared_hosting_get_matches(response):
        regex = '<h3><a\shref="(.*?)"\sonmousedown="'
        mo = re.finditer(regex, response)
        urls = []
        for i in mo:
            urls.extend(i.groups())
        return urls
    
    def bing_shared_hosting_query_bing(ip_str):
        body = urllib2.urlopen(bing_url+ip_str).read()
        if not no_results_string in body:
            for i in bing_shared_hosting_get_matches(body):
                result(ip_str+" : "+i)
        else:
            error("Bing page did not show '"+no_results_string+"' for ip: "+ip_str)

    info("Starting bing shared hosting search. I'm not printing anything until i find something")
    info("This method is only searching through the first result page of bing!")    
    for ip in getIpRangeList(ip_start, ip_end):
        bing_shared_hosting_query_bing(ip)


def getIpRangeList(ip_start, ip_end):

    result_list = []

    one, two, three, four = ip_start.split('.')
    one, two, three, four = (int(one), int(two), int(three), int(four))
    end_one, end_two, end_three, end_four = ip_end.split('.')
    end_one, end_two, end_three, end_four = (int(end_one), int(end_two), int(end_three), int(end_four))

    while one <= end_one:
        end_two_tmp = end_two
        if not one == end_one:
            end_two_tmp = 255
        while two <= end_two_tmp:
            end_three_tmp = end_three
            if not two == end_two:
                end_three_tmp = 255
            while three <= end_three_tmp:
                end_four_tmp = end_four
                if not three == end_three:
                    end_four_tmp = 255
                while four <= end_four_tmp:
                    result_list.append("%i.%i.%i.%i"%(one, two, three, four))
                    #debug(str(one)+" "+str(two)+" "+str(three)+" "+str(four))
                    four += 1
                four = 0
                three += 1
            three = 0
            two += 1
        two = 0
        one += 1
    
    return result_list

   
def error(*text):
    print "[PY-ERROR] "+str(" ".join(str(i) for i in text))
    if SLEEP_TIME_ON_ERROR > 0:
        sleep(SLEEP_TIME_ON_ERROR)

def result(*text):
    print "[PY-RESULT] "+str(" ".join(str(i) for i in text))

def info(*text):
    print "[PY-INFO] "+str(" ".join(str(i) for i in text))

def debug(*text):
    print "[PY-DEBUG] "+str(" ".join(str(i) for i in text))

printBingSharedHosting("74.125.39.103", "74.125.39.106")

I admit, the getIpRangeList function could be a little bit more elegant, but I didn’t want to use an external library, didn’t find any suitable code snippet and in the end, it does its job.

AES encryption/decryption in python

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Sometimes I just need some encryption, so I wrote a script that fits some cases. The functions use the python Crypto library.

The security of the used encryption is ok, I wrote a PBKDF2-like Key Derivation Function, that hashes the password before truncating and using it as the AES key. The encryption function does not add random padding. This means an attacker can guess how long the plaintext was. Additionally, CBC is a non-authenticated mode, therefore if somebody flips a bit in your ciphertext the decryption routine won’t notice. This usually means an attacker can flip one bit, but the remaining blocks will be corrupted. So flipping a bit in the last block is easy. Moreover 13’370 derivation rounds might be too much or not enough for you.

def AESencrypt(password, plaintext, base64=False):
    import hashlib, os
    from Crypto.Cipher import AES
    SALT_LENGTH = 32
    DERIVATION_ROUNDS=13370
    BLOCK_SIZE = 16
    KEY_SIZE = 32
    MODE = AES.MODE_CBC
    
    salt = os.urandom(SALT_LENGTH)
    iv = os.urandom(BLOCK_SIZE)
    
    paddingLength = 16 - (len(plaintext) % 16)
    paddedPlaintext = plaintext+chr(paddingLength)*paddingLength
    derivedKey = password
    for i in range(0,DERIVATION_ROUNDS):
        derivedKey = hashlib.sha256(derivedKey+salt).digest()
    derivedKey = derivedKey[:KEY_SIZE]
    cipherSpec = AES.new(derivedKey, MODE, iv)
    ciphertext = cipherSpec.encrypt(paddedPlaintext)
    ciphertext = ciphertext + iv + salt
    if base64:
        import base64
        return base64.b64encode(ciphertext)
    else:
        return ciphertext.encode("hex")

def AESdecrypt(password, ciphertext, base64=False):
    import hashlib
    from Crypto.Cipher import AES
    SALT_LENGTH = 32
    DERIVATION_ROUNDS=13370
    BLOCK_SIZE = 16
    KEY_SIZE = 32
    MODE = AES.MODE_CBC
    
    if base64:
        import base64
        decodedCiphertext = base64.b64decode(ciphertext)
    else:
        decodedCiphertext = ciphertext.decode("hex")
    startIv = len(decodedCiphertext)-BLOCK_SIZE-SALT_LENGTH
    startSalt = len(decodedCiphertext)-SALT_LENGTH
    data, iv, salt = decodedCiphertext[:startIv], decodedCiphertext[startIv:startSalt], decodedCiphertext[startSalt:]
    derivedKey = password
    for i in range(0, DERIVATION_ROUNDS):
        derivedKey = hashlib.sha256(derivedKey+salt).digest()
    derivedKey = derivedKey[:KEY_SIZE]
    cipherSpec = AES.new(derivedKey, MODE, iv)
    plaintextWithPadding = cipherSpec.decrypt(data)
    paddingLength = ord(plaintextWithPadding[-1])
    plaintext = plaintextWithPadding[:-paddingLength]
    return plaintext
    
a = AESencrypt("password", "ABC")
print AESdecrypt("password", a)

Automating JD-GUI decompilation on a Mac with AppleScript

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I know the guys over at Java Decompiler don’t want to release a command line tool, because they fear that companies will use their code in commercial product. See the discussion here. I found a solution to my problem, so that I can still automate the decompilation process. During my Android research I really need to decompile a lot of jar files, therefore I wrote a simple AppleScript that saves me the sources to my /opt folder.

tell application "JD-GUI"
	activate
end tell

tell application "System Events"
	keystroke "s" using {command down, option down}
end tell
tell application "System Events"
	keystroke tab
	keystroke tab
	keystroke tab
	key code 125 #Down
	key code 125 #Down
	key code 125 #Down
	key code 125 #Down
	key code 125 #Down
	key code 36 #Enter
	delay 1
	key code 36 #Enter
	delay 2
end tell

repeat while appIsRunning("JD-GUI")
	tell application "System Events"
		keystroke "q" using {command down} #Close JD-GUI
	end tell
	delay 2
end repeat

on appIsRunning(appName)
	tell application "System Events" to (name of processes) contains appName
end appIsRunning

After saving the script as decompile_jar.applescript with the AppleScript Editor, you can invoke it from your bash script like this:

/Applications/JD-GUI.app/Contents/MacOS/jd-gui example.jar &
sleep 1
osascript decompile_jar.applescript
mv /opt/example.src.zip /your/destination