解决ASP(图像)上传漏洞的方法
上一篇 / 下一篇 2008-04-16 10:04:22 / 个人分类:ASP
针对此情况使用下列函数进行辨别:51Testing软件测试网$V,sxz"o0|{
<%51Testing软件测试网#P!do4L~
'******************************************************************51Testing软件测试网?&R*nkTW;u
'CheckFileType 函数用来检查文件是否为图片文件
9M`|R4Fq~ h#Z0'参数filename是本地文件的路径
8zk3nB9?;B:_K0'如果是文件jpeg,gif,bmp,png图片中的一种,函数返回true,否则返回false
,YB`mV6r0'******************************************************************
;k*Zn"VH2^)t:r0const adTypeBinary=1
9X [ M,Tj3w?"H0L,g,}0dim jpg(1):jpg(0)=CByte(&HFF):jpg(1)=CByte(&HD8)51Testing软件测试网(Jq1J;W oh#N(Z*x
dim bmp(1):bmp(0)=CByte(&H42):bmp(1)=CByte(&H4D)
Y\1r:C2k4k#F0_ C0dim png(3):png(0)=CByte(&H89):png(1)=CByte(&H50):png(2)=CByte(&H4E):png(3)=CByte(&H47)
F\gay'a-~!]L'NV0dim gif(5):gif(0)=CByte(&H47):gif(1)=CByte(&H49):gif(2)=CByte(&H46):gif(3)=CByte(&H39):gif(4)=CByte(&H38):gif(5)=CByte(&H61)
#s-`*y\c#Y}Q'Q0function CheckFileType(filename)51Testing软件测试网N+Glbs*c
on error resume next51Testing软件测试网5~1Y(RuAjq?(A/N(X(X
CheckFileType=false
b^;qr:E0dim fstream,fileExt,stamp,i
*rwt@&[j0fileExt=mid(filename,InStrRev(filename,".")+1)51Testing软件测试网%Os%t Q+@]2M
set fstream=Server.createobject("ADODB.Stream")
e R!Po"L$^Fz$B1d0fstream.Open51Testing软件测试网DC:G.nI sO(b
fstream.Type=adTypeBinary
/Gf,B[ |8Vf6s0fstream.LoadFromFile filename
w)w?/r%qZX0fstream.position=051Testing软件测试网/kl7L g,vS*u x
select case fileExt
7? d3y!eA*]0case "jpg","jpeg"51Testing软件测试网jL0cq0pzf
stamp=fstream.read(2)51Testing软件测试网3K:BI.slQ
for i=0 to 1
r"btW]4TQ0if ascB(MidB(stamp,i+1,1))=jpg(i) then CheckFileType=true else CheckFileType=false51Testing软件测试网fV'I#V{ S1kL(kt
next
$F!t(pAjl9} KJ#_0case "gif"
R,v'x#ij+c0stamp=fstream.read(6)
Z(i)G'\5q tI$t G0for i=0 to 5
%C;owb2WW%u%s+_0if ascB(MidB(stamp,i+1,1))=gif(i) then CheckFileType=true else CheckFileType=false51Testing软件测试网F$nD2k` [[{
next
I:?eh Kmio0case "png"
Z`*k e8XR[BtqN0stamp=fstream.read(4)51Testing软件测试网4X b:O DqQ[I;[
for i=0 to 3
}k){ ]4xn X0if ascB(MidB(stamp,i+1,1))=png(i) then CheckFileType=true else CheckFileType=false51Testing软件测试网"Ye:_Z0A6A9P'd
next
v4Q4TsF i0case "bmp"
9oQ3O?"r)nB#{"w0stamp=fstream.read(2)
rW:OWRr+vxm0for i=0 to 1
/{Hk.`+?A#U*Z}+J0if ascB(MidB(stamp,i+1,1))=bmp(i) then CheckFileType=true else CheckFileType=false
_2V^:[U4l0next51Testing软件测试网fB6y5aM0t6c
end select
K~2Pf+L0fstream.Close51Testing软件测试网W4Ed_9u
set fseteam=nothing
bc2Z$A{pNKC B0if err.number<>0 then CheckFileType=false
1V@;Ov;[,|,y0end function
zoxUu0%>
c.T]q#UR0那么在应用的时候51Testing软件测试网 a4PLr+L'Er R
CheckFileType(server.mappath("cnbruce.jpg"))
$_kL^O2eW-c0或者
8?2Yl \K@#P9j ]6i0CheckFileType("F:/web/164/images/cnbruce.jpg"))51Testing软件测试网,VRaN UHG*z
反正即是检测验证本地物理地址的图像文件类型,返回 true 或 false值51Testing软件测试网V\B3J&z1NXE)X2{
所以这个情况应用在图像上传中,目前的办法是先允许该“伪图像”文件的上传,接着使用以上的自定义函数判断该文件是否符合图像的规范,若是木马伪装的图像文件则FSO删除之,比如:
Q:T7q F;`|[ N`CA;c0,Fsiix@7?"_Gk_0 n-aKWZ?0file.SaveAs Server.mappath(filename) '保存文件51Testing软件测试网&_4~VIT y If not CheckFileType(Server.mappath(filename)) then51Testing软件测试网%lRGt:f response.write "错误的图像格式"51Testing软件测试网%yI:GteQKM Set fso = CreateObject("scrīpting.FileSystemObject")51Testing软件测试网1Te8o/VR Set ficn = fso.GetFile(Server.mappath(filename))51Testing软件测试网?V^{ G5TQ d-c ficn.delete 9D/bz.v G0set ficn=nothing U.v q'twsJ0xT T0set fso=nothing51Testing软件测试网p*jIA/| a q)g response.end c$Nc6b i S5G0end if51Testing软件测试网8E'U$T,@ U.zNT "s}W"r k`w"u0 |
则是先将文件上传,接着立马使用自定义函数判断文件图像类型的吻合性,FSO做出删除该文件的操作。51Testing软件测试网0fy(U!S+hF*J1oZd yq_
ASP上传漏洞还利用"\0"对filepath进行手脚操作51Testing软件测试网;s+mY)r+QFK"gn
http://www.hzd0.blog.163.com/blog/showlog.asp?cat_id=32&log_id=635
-c;U$T8eA*p0针对这样的情况可使用如下函数
yF;[],e(t051Testing软件测试网-}'am(ep
B-[zf4T*~'@v-YH;~*V0 function TrueStr(fileTrue)51Testing软件测试网/pF*[^$v^ str_len=len(fileTrue) Zc&n.VY-EPi,V0pos=Instr(fileTrue,chr(0))51Testing软件测试网,[!T+PG&i&d$^vo if pos=0 or pos=str_len then51Testing软件测试网.za7x1LKzaX TrueStr=true c L@E;| s b^!s$Ht0else51Testing软件测试网-sn#gEl TrueStr=false -|mJ*T4Y*n6H a,jg5Q0end if ;nt$m+`Vq"m0end function51Testing软件测试网^%U,V1A#M Y0p 51Testing软件测试网"b.S|@5|)A |
接着就可判断后再做文件的上传
R _ W.S8f5V9nw,X0,NBU(Ih0 P$Z7w^v)m+FY0if TrueStr(filename)=false then51Testing软件测试网bj}1t(E+l response.write "非法文件"51Testing软件测试网hAQG0?S(G response.end Uw[5A"^V+L0end if `8{+vkG7kZ6B&{X3Q0file.SaveAs Server.mappath(filename)51Testing软件测试网Hy:MY)GxV5C8| ]4twB`X0 |
l~ps tJ0
.Xk@/e9a7HKa5}0%kBT7F/|B/YQ0 51Testing软件测试网K3mJ7o,|n$P3Y8r
@.l}B B;u,|#e0可将以下代码拷到DW再自行修改:51Testing软件测试网_c'kjf,_
5x+@/m
j6w7Npr0<%@LANGUAGE="VBscrīpt" CODEPAGE="936"%>
)Xc1H9o'\8I2s7`Ad0<!--#include file="upload.inc"-->51Testing软件测试网6W.lCo3H0]/KbZw
<html>51Testing软件测试网(G,Z'o&f
[K
S+G7\@
<head>51Testing软件测试网d)yg
C!c
@#T
<title>文件上传</title>
Q+g_U
}.Eu0<meta http-equiv="content-type" content="text/html;charset=gb2312">
ipQ @*z&Iy5T]*~0</head>
zv:fR[y0<body>
7}y2U2l/l0<%51Testing软件测试网IfltD)qP;Gp
F*y
on error resume next51Testing软件测试网cW3a,\:nge\)|,X
dim upload,f_folder,file,formPath,iCount,filename,fileExt,filesizemin,filesizemax
8N-Nn
?&i/? RF|0'******************************************************************51Testing软件测试网F&xm[K}-D
'CheckFileType 函数用来检查文件是否为图片文件
b4N)Y N2N[0'参数filename是本地文件的路径51Testing软件测试网2wz'T6y-^J%zM,U3@
'如果是文件jpeg,gif,bmp,png图片中的一种,函数返回true,否则返回false
]2w Z6|n+~%A0'******************************************************************51Testing软件测试网$a1v6fO:U3uvQ
const adTypeBinary=151Testing软件测试网&LV"KVFgw
dim jpg(1):jpg(0)=CByte(&HFF):jpg(1)=CByte(&HD8)51Testing软件测试网3f'BI+I-} ].Y$kF|
dim bmp(1):bmp(0)=CByte(&H42):bmp(1)=CByte(&H4D)
V1s@Jtj*z"d4m,Z0dim png(3):png(0)=CByte(&H89):png(1)=CByte(&H50):png(2)=CByte(&H4E):png(3)=CByte(&H47)51Testing软件测试网]FQhT*r
dim gif(5):gif(0)=CByte(&H47):gif(1)=CByte(&H49):gif(2)=CByte(&H46):gif(3)=CByte(&H39):gif(4)=CByte(&H38):gif(5)=CByte(&H61)
function CheckFileType(filename)51Testing软件测试网 ]%Mh'WC/J^.L
CheckFileType=false
{3xV'p#[!C]q}$X0dim fstream,fileExt,stamp,i
H!]nTV.QG0w
d0fileExt=mid(filename,InStrRev(filename,".")+1)
-@6P8y6BR"|G1w:U0set fstream=Server.createobject("ADODB.Stream")51Testing软件测试网-|+@
W
d;p(p@8B|m
fstream.Open
3TsLKfcAi0fstream.Type=adTypeBinary51Testing软件测试网|f l\ x*J%_4A
fstream.LoadFromFile filename
|3o.`7a@#c0fstream.position=051Testing软件测试网4I%I.VyN9Y|6E
select case fileExt51Testing软件测试网
@![2lE!t2rO
case "jpg","jpeg"51Testing软件测试网$K!kd2h2S
stamp=fstream.read(2)51Testing软件测试网M+[8ks%OX"X
for i=0 to 1
vRx.\X2} s2o-P0if ascB(MidB(stamp,i+1,1))=jpg(i) then CheckFileType=true else CheckFileType=false51Testing软件测试网Dl9]]6q|'Ug
next
{}s2N0XBs1r`0case "gif"
tlEcS5ij1s0stamp=fstream.read(6)51Testing软件测试网D+]0f8eL:D7vU+n
for i=0 to 5
Rn`3sFEbF:^0if ascB(MidB(stamp,i+1,1))=gif(i) then CheckFileType=true else CheckFileType=false51Testing软件测试网U+^,L~z+wb{ ?RF
next51Testing软件测试网R4m*i,^8t
K-I
case "png"51Testing软件测试网8s1O9c1s(^
stamp=fstream.read(4)51Testing软件测试网aW
yj9p| ~7oz
for i=0 to 351Testing软件测试网| t6hR4aD w
if ascB(MidB(stamp,i+1,1))=png(i) then CheckFileType=true else CheckFileType=false
/WWl G G Z0next51Testing软件测试网;v5K_$AhZz
case "bmp"51Testing软件测试网RnzHl:b
stamp=fstream.read(2)51Testing软件测试网$JyD8o;^)i
n:} G
for i=0 to 1
MR-K X6g5L_0kVT!K&B4P]0if ascB(MidB(stamp,i+1,1))=bmp(i) then CheckFileType=true else CheckFileType=false51Testing软件测试网;^^(zN+u$s6{2G v
X7^
next51Testing软件测试网V`H9Y6O%y
end select
W7t{c'W$uT3Ew#u]0fstream.Close51Testing软件测试网 OO:B#nP
set fseteam=nothing51Testing软件测试网+u!`3f!Ia@;[
if err.number<>0 then CheckFileType=false
/gD M?@"| uqV0end function
function TrueStr(fileTrue)
"?riL&G.f,e&P0 str_len=len(fileTrue)
H:[0v
_7FiiUY%f7A0 pos=Instr(fileTrue,chr(0))
;K
ZU,d(X.yX0 if pos=0 or pos=str_len then51Testing软件测试网 I#|q?Sz
TrueStr=true51Testing软件测试网kD4g"Y&X&zbU fM1ntk
else51Testing软件测试网 pu8N?N&ST`O_+|
TrueStr=false51Testing软件测试网5gi f8T&@!y9v?A
end if51Testing软件测试网.oFsd3z0Y+J
end function51Testing软件测试网1X)L8l-D&i`
filesizemin=10051Testing软件测试网eXEu/Q8XW3~+Is
filesizemax=200*1024
2F3J'[C*Wn;p
b0set upload=new upload_5xSoft '建立上传对象51Testing软件测试网&s(f;YgB?
h#Gn
f_folder=upload.form("upfilefolder")51Testing软件测试网B
cY
\V@UV2p
xQt
r
]'A^3v8r9H/t0'********************************列出所有上传文件***************************************************51Testing软件测试网9zrZP3g1g6w
For each formName in upload.objFile
5r0]6z7O8S"F,G7c}.m+IA
W0set file=upload.file(formName)
:P&UK H1W+F.|0If file.filesize>0 then
'********************************检测文件大小***************************************************51Testing软件测试网)[+n|wW(MW
If file.filesize<filesizemin Then51Testing软件测试网u^XL1\bg
response.write "你上传的文件太小了 [ <a href=# ōnclick=history.go(-1)>重新上传</a> ]"51Testing软件测试网C0?2x3M(RJXN$C?
ElseIf file.filesize>filesizemax then51Testing软件测试网*q'D]|A9]"V6qJ
response.write "文件大小超过了 "&filesizemax&"字节 限制 [ <a href=# ōnclick=history.go(-1)>重新上传</a> ]"51Testing软件测试网
S
vT_5B*o H5{1~*I
End If
9jWtP'p|X4d0 '********************************检测文件类型****************************************************51Testing软件测试网&nOGwyk7_f4~
fileExt=ucase(right(file.filename,4))
*K{T7Q@F.JwW4D0 uploadsuc=false51Testing软件测试网)hm8o2r
C-Q
Forum_upload="RAR|ZIP|SWF|JPG|PNG|GIF|DOC|TXT|CHM|PDF|ACE|MP3|WMA|WMV|MIDI|AVI|RM|RA|RMVB|MOV|XLS"51Testing软件测试网;Ra1?ECm I
Forumupload=split(Forum_upload,"|")51Testing软件测试网 Q8m Xu
xrp
for i=0 to ubound(Forumupload)
g6iYKm5rZA0 if fileEXT="."&trim(Forumupload(i)) then51Testing软件测试网QV R,w;SfjL
uploadsuc=true
~ Gp;nL)p3q0 exit for51Testing软件测试网NF"v[
X{&P4\?
else
$|V!i%O0h0C;Y9l0 uploadsuc=false51Testing软件测试网(Pw!b(~!Q
end if
+UP+~
V,V,F4S X0 next51Testing软件测试网%fy/[s8W%r5G
if uploadsuc=false then51Testing软件测试网T-x$Q4FX3o
response.write "文件格式不正确 [ <a href=# ōnclick=history.go(-1)>重新上传</a> ]"51Testing软件测试网B"e$V5f
F?8l$^
response.end51Testing软件测试网$E,i`-a:M
end if51Testing软件测试网*bn&U_ ?+[*q!UQ
/EjDZ;Y8oTi0 '********************************建立文件上传的目录文件夹****************************************51Testing软件测试网7H cITGV2d
Set upf=Server.CreateObject("scrīpting.FileSystemObject")
"S k]uL/Na0 If Err<>0 Then
Lp'T7_%aH#jq0 Err.Clear
.s2Ur8h"{*{_hf0 response.write("您的服务器不支持FSO")51Testing软件测试网N2e&qc*Ag
i$\
response.end
.TfS-HG^ ~0 End If51Testing软件测试网]a+Kl,E:] G
f_type= replace(fileExt,".","")51Testing软件测试网a3}c:W"{9aQ3B
f_name= year(now)&"-"&month(now)51Testing软件测试网't6pv.h/|5{ i|F U
If upf.FolderExists(Server.MapPath(f_folder&"/"&f_type&"/"&f_name))=False Then51Testing软件测试网+E(a
GD5^m:\,^:f
If upf.FolderExists(Server.MapPath(f_folder&"/"&f_type))=False Then
\sl3Z"E0 If upf.FolderExists(Server.MapPath(f_folder))=False Then
M&Y.j.s#T4I:V9I0 upf.CreateFolder Server.MapPath(f_folder)51Testing软件测试网XwzHvux!u
upf.CreateFolder Server.MapPath(f_folder&"/"&f_type)
/D!UKg#B
| [6CY0 upf.CreateFolder Server.MapPath(f_folder&"/"&f_type&"/"&f_name)51Testing软件测试网"{0pr}i@
Else51Testing软件测试网o4BS3goE{
upf.CreateFolder Server.MapPath(f_folder&"/"&f_type)51Testing软件测试网bY R ~4_H]X
~
upf.CreateFolder Server.MapPath(f_folder&"/"&f_type&"/"&f_name)
8tsw`9T
['\p
|,}0 End If
GV!X2O9{%CSS0 Else51Testing软件测试网dIr*Yq@x9h8P ?
upf.CreateFolder Server.MapPath(f_folder&"/"&f_type&"/"&f_name)
vXB!c9a)\*\g/O0 End If
-O.FT$A
OU(J'~0 End If51Testing软件测试网*w(H!_
B1y
f_ftn=f_folder&"/"&f_type&"/"&f_name
e4M;w s,rR0 Set upf=Nothing51Testing软件测试网+FWTH*{q}M}/y
v4e2GX9nZw0 '********************************保存上传文件至文件夹*****************************************
'H5i
bv.]*rg;}0 randomize
Ym9HbF5Gk9uh0 ranNum=int(90000*rnd)+10000
8B9p6i`8irJ0 filename=f_ftn&"/"&day(now)&"-"&ranNum&"-"&file.filename51Testing软件测试网.i,Q1~n%s$rr
if TrueStr(filename)=false then
1@ |
cG3Q-D'hS5@*A0 response.write "非法文件"
(l&`(R"y(tq3qdqW0 response.end51Testing软件测试网2Fnl"^-ast
end if51Testing软件测试网*]3nOpRx
if file.filesize>filesizemin and file.filesize<filesizemax then51Testing软件测试网1Gx"Ay#e;^*A+RSz
file.SaveAs Server.mappath(filename) '保存文件51Testing软件测试网
W\8nYY1Q4{"T'wF1D7Pc
if f_type="JPG" or f_type="GIF" or f_type="PNG" then51Testing软件测试网iVw$juN
If not CheckFileType(Server.mappath(filename)) then51Testing软件测试网7]
h0Be7X
response.write "错误的图像格式 [ <a href=# ōnclick=history.go(-1)>重新上传</a> ]"
xHr-jt0 Set fso = CreateObject("scrīpting.FileSystemObject")51Testing软件测试网Wovn.FQ7A6b\
Set ficn = fso.GetFile(Server.mappath(filename))
o9Dn Z.?[d4^cC0 ficn.delete
*d;Bu"W
e.{7r.I#D
Ur0 set ficn=nothing
Zy1H Q7pe's+D7k0 set fso=nothing51Testing软件测试网*|4B1m9n/`R)I
response.end51Testing软件测试网-rz`h/h^ V,g
end if
J'B*_
p5^qA0 response.write "<scrīpt>parent.cn_bruce.cn_content.value+='[img]"&filename&"[/img]'</scrīpt>"
OG%upW0 ElseIf f_type="ZIP" or f_type="RAR" or f_type="DOC" or f_type="TXT" then51Testing软件测试网5LT\,x ]&o+s
response.write "<scrīpt>parent.cn_bruce.cn_content.value+='[url]"&filename&"[/url]'</scrīpt>"
:vI@Y.GzI-h0 'ElseIf51Testing软件测试网 J?b-E u\1HA7gz
else51Testing软件测试网,}K$uN/D*@)H
response.write "<scrīpt>parent.cn_bruce.cn_content.value+=' "&filename&" '</scrīpt>"
k.`S#^@~2l;S_0 end if51Testing软件测试网:O D6\I
y9C+W
iCount=iCount+151Testing软件测试网h8TN|
i
end if51Testing软件测试网r1x'm6r],K"ai*O
set file=nothing
Ya8u.kX$NOif0end if
(J ~#z$t"^0L`8p0next
8a o(D}!Fu)T9v0set upload=nothing '删除此对象51Testing软件测试网 ^y(lh
_$r'U2]%i
response.write (iCount&" 个文件上传成功! <a href=# ōnclick=history.go(-1)>继续上传</a>")51Testing软件测试网MPb*^k1v(m
%>
%p F p
F~~P0</body>51Testing软件测试网 Q6e
sLzb
</html>
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]:R051Testing软件测试网A7B%J
yQ8Z@-c%JE
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