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# System prepended metadata

title: 攻防期末

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web bug
===
1)
Why could a user utilize a web bug to trace whether his e-mail has been read or whether his web page 
Ans:
在信件裡面放一個1x1像素的外部圖片，當收件人打開信件時，就會向圖片所在server發出請求，以此記錄下收件人已打開信件，web page也是相同原理

2)
By inserting a web bug to a web page, a user can obtain what information from the computer whose browser is displaying the web page? 
(意指 我可以從 要引用我照片的人 取得哪些資訊)
Ans:
1. IP addr of 請求者
2. 請求內容的時間
3. type of web browser 
4. 上次set的cookies是否還存在

HTTP cookies
===
3)
What are the functions of HTTP cookies?
Ans:
1. authenticating, 
2. tracking, 
3. 保存用戶特定資料，如購物用的購物車

XSS
===
4)
List two ways that a malicious user could use to have a web browser execute her/his code (P.S. This code could be written in JavaScript).
Ans:
1. 直接透過script tag 來執行javascript
2. 透過Hyperlinks 與 criteria配合SCRIPT，當victim click超連結時，server回傳頁面與惡意程式碼並執行

5)
When a web server application does not execute what examination(檢查), then an XSS vulnerability may be created?
Ans:
沒有根據user 的input 進行檢查篩選，如script的html tag 就要讓他無效化


6)
Who are the most common victims to XSS?
Ans:
1. CGI scripts,
2. search engincs.
3. interactive bulletin boards,

7)
To complete a successful CSRF attack, what 3 preconditions(前提) must be satisfied?
Ans:
1. attacker了解victim目前在哪些網站上被認證過
2. 目標網站對登入沒有二次認證
3. victim具有目標網站的auth cookie且未過期

SQL
===
8)
major responsibility of creating SQL vulnerability on a web service?
Ans:
application programs used by the web service to create SQL queries

DOS/DDOS
===
9)
(1) What are the two DoS/DDoS attack categories? 
(2) For each category, list at least two DoS/DDoS attacks that belong to it.
Ans:
Flood Attack:
* TCP SYN Flood Attack
* UDP Flood Attack

Low and slow:

Malformed Packet:
* Ping of Death Attack
* TearDrop Attack
* Land Attack

10) 
What network services are utilized by attackers to launch a Smurf flood attack?
Ans:
ICMP echo request service.

11) 
IP spoofing is frequently used in network attacks to hide the attack sources. Could every kind of DoS/DDoS attacks use this approach to hide the hosts that generate the DoS/DDoS attack packets?
Ans: 
TCP SYN Floods不一定依賴IP欺騙來隱藏攻擊的來源。攻擊者可以使用其真實的IP地址。

12)
In order to launch a DoS/DDoS attack, an attacker always needs to send plenty of attack IP packeis to the chosen target host. Is the above claim correct? Give your rcasons.
Ans:
NO , Malformed(畸形)packet attack 可以送少量的packet

13) 
List two countermeasures of DoS/DDoS Attacks. 
Ans:
Disable unnecessary network services.
Backtracking attack paths，在上游的路由器安裝filters，儘早過濾掉attack流量。

14)
List 3 kinds of information that a rootkit want to hide.
Ans：
running processes
files
system data
