RDP
The Remote Desktop Protocol (RDP) is a protocol developed by Microsoft for remote access to a computer running the Windows operating system. This protocol allows display and control commands to be transmitted via the GUI encrypted over IP networks. RDP works at the application layer in the TCP/IP reference model, typically utilizing TCP port 3389 as the transport protocol. However, the connectionless UDP protocol can use port 3389 also for remote administration.
For an RDP session to be established, both the network firewall and the firewall on the server must allow connections from the outside. If Network Address Translation (NAT) is used on the route between client and server, as is often the case with Internet connections, the remote computer needs the public IP address to reach the server. In addition, port forwarding must be set up on the NAT router in the direction of the server.
Footprinting the Service
Scanning the RDP service can quickly give us a lot of information about the host. For example, we can determine if NLA is enabled on the server or not, the product version, and the hostname.
neutron@kali[/kali]$ nmap -sV -sC 10.129.201.248 -p3389 --script rdp*
Starting Nmap 7.92 ( https://nmap.org ) at 2021-11-06 15:45 CET
Nmap scan report for 10.129.201.248
Host is up (0.036s latency).
PORT STATE SERVICE VERSION
3389/tcp open ms-wbt-server Microsoft Terminal Services
| rdp-enum-encryption:
| Security layer
| CredSSP (NLA): SUCCESS
| CredSSP with Early User Auth: SUCCESS
|_ RDSTLS: SUCCESS
| rdp-ntlm-info:
| Target_Name: ILF-SQL-01
| NetBIOS_Domain_Name: ILF-SQL-01
| NetBIOS_Computer_Name: ILF-SQL-01
| DNS_Domain_Name: ILF-SQL-01
| DNS_Computer_Name: ILF-SQL-01
| Product_Version: 10.0.17763
|_ System_Time: 2021-11-06T13:46:00+00:00
Service Info: OS: Windows; CPE: cpe:/o:microsoft:windows
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 8.26 seconds
In addition, we can use --packet-trace to track the individual packages and inspect their contents manually. We can see that the RDP cookies (mstshash=nmap) used by Nmap to interact with the RDP server can be identified by threat hunters and various security services such as Endpoint Detection and Response (EDR), and can lock us out as penetration testers on hardened networks.
neutron@kali[/kali]$ nmap -sV -sC 10.129.201.248 -p3389 --packet-trace --disable-arp-ping -n
Starting Nmap 7.92 ( https://nmap.org ) at 2021-11-06 16:23 CET
SENT (0.2506s) ICMP [10.10.14.20 > 10.129.201.248 Echo request (type=8/code=0) id=8338 seq=0] IP [ttl=53 id=5122 iplen=28 ]
SENT (0.2507s) TCP 10.10.14.20:55516 > 10.129.201.248:443 S ttl=42 id=24195 iplen=44 seq=1926233369 win=1024 <mss 1460>
SENT (0.2507s) TCP 10.10.14.20:55516 > 10.129.201.248:80 A ttl=55 id=50395 iplen=40 seq=0 win=1024
SENT (0.2517s) ICMP [10.10.14.20 > 10.129.201.248 Timestamp request (type=13/code=0) id=8247 seq=0 orig=0 recv=0 trans=0] IP [ttl=38 id=62695 iplen=40 ]
RCVD (0.2814s) ICMP [10.129.201.248 > 10.10.14.20 Echo reply (type=0/code=0) id=8338 seq=0] IP [ttl=127 id=38158 iplen=28 ]
SENT (0.3264s) TCP 10.10.14.20:55772 > 10.129.201.248:3389 S ttl=56 id=274 iplen=44 seq=2635590698 win=1024 <mss 1460>
RCVD (0.3565s) TCP 10.129.201.248:3389 > 10.10.14.20:55772 SA ttl=127 id=38162 iplen=44 seq=3526777417 win=64000 <mss 1357>
NSOCK INFO [0.4500s] nsock_iod_new2(): nsock_iod_new (IOD #1)
NSOCK INFO [0.4500s] nsock_connect_tcp(): TCP connection requested to 10.129.201.248:3389 (IOD #1) EID 8
NSOCK INFO [0.4820s] nsock_trace_handler_callback(): Callback: CONNECT SUCCESS for EID 8 [10.129.201.248:3389]
Service scan sending probe NULL to 10.129.201.248:3389 (tcp)
NSOCK INFO [0.4830s] nsock_read(): Read request from IOD #1 [10.129.201.248:3389] (timeout: 6000ms) EID 18
NSOCK INFO [6.4880s] nsock_trace_handler_callback(): Callback: READ TIMEOUT for EID 18 [10.129.201.248:3389]
Service scan sending probe TerminalServerCookie to 10.129.201.248:3389 (tcp)
NSOCK INFO [6.4880s] nsock_write(): Write request for 42 bytes to IOD #1 EID 27 [10.129.201.248:3389]
NSOCK INFO [6.4880s] nsock_read(): Read request from IOD #1 [10.129.201.248:3389] (timeout: 5000ms) EID 34
NSOCK INFO [6.4880s] nsock_trace_handler_callback(): Callback: WRITE SUCCESS for EID 27 [10.129.201.248:3389]
NSOCK INFO [6.5240s] nsock_trace_handler_callback(): Callback: READ SUCCESS for EID 34 [10.129.201.248:3389] (19 bytes): .........4.........
Service scan match (Probe TerminalServerCookie matched with TerminalServerCookie line 13640): 10.129.201.248:3389 is ms-wbt-server. Version: |Microsoft Terminal Services|||
...SNIP...
NSOCK INFO [6.5610s] nsock_write(): Write request for 54 bytes to IOD #1 EID 27 [10.129.201.248:3389]
NSE: TCP 10.10.14.20:36630 > 10.129.201.248:3389 | 00000000: 03 00 00 2a 25 e0 00 00 00 00 00 43 6f 6f 6b 69 *% Cooki
00000010: 65 3a 20 6d 73 74 73 68 61 73 68 3d 6e 6d 61 70 e: mstshash=nmap
00000020: 0d 0a 01 00 08 00 0b 00 00 00
...SNIP...
NSOCK INFO [6.6820s] nsock_write(): Write request for 57 bytes to IOD #2 EID 67 [10.129.201.248:3389]
NSOCK INFO [6.6820s] nsock_trace_handler_callback(): Callback: WRITE SUCCESS for EID 67 [10.129.201.248:3389]
NSE: TCP 10.10.14.20:36630 > 10.129.201.248:3389 | SEND
NSOCK INFO [6.6820s] nsock_read(): Read request from IOD #2 [10.129.201.248:3389] (timeout: 5000ms) EID 74
NSOCK INFO [6.7180s] nsock_trace_handler_callback(): Callback: READ SUCCESS for EID 74 [10.129.201.248:3389] (211 bytes)
NSE: TCP 10.10.14.20:36630 < 10.129.201.248:3389 |
00000000: 30 81 d0 a0 03 02 01 06 a1 81 c8 30 81 c5 30 81 0 0 0
00000010: c2 a0 81 bf 04 81 bc 4e 54 4c 4d 53 53 50 00 02 NTLMSSP
00000020: 00 00 00 14 00 14 00 38 00 00 00 35 82 8a e2 b9 8 5
00000030: 73 b0 b3 91 9f 1b 0d 00 00 00 00 00 00 00 00 70 s p
00000040: 00 70 00 4c 00 00 00 0a 00 63 45 00 00 00 0f 49 p L cE I
00000050: 00 4c 00 46 00 2d 00 53 00 51 00 4c 00 2d 00 30 L F - S Q L - 0
00000060: 00 31 00 02 00 14 00 49 00 4c 00 46 00 2d 00 53 1 I L F - S
00000070: 00 51 00 4c 00 2d 00 30 00 31 00 01 00 14 00 49 Q L - 0 1 I
00000080: 00 4c 00 46 00 2d 00 53 00 51 00 4c 00 2d 00 30 L F - S Q L - 0
00000090: 00 31 00 04 00 14 00 49 00 4c 00 46 00 2d 00 53 1 I L F - S
000000a0: 00 51 00 4c 00 2d 00 30 00 31 00 03 00 14 00 49 Q L - 0 1 I
000000b0: 00 4c 00 46 00 2d 00 53 00 51 00 4c 00 2d 00 30 L F - S Q L - 0
000000c0: 00 31 00 07 00 08 00 1d b3 e8 f2 19 d3 d7 01 00 1
000000d0: 00 00 00
...SNIP...
A Perl script named rdp-sec-check.pl has also been developed by Cisco CX Security Labs that can unauthentically identify the security settings of RDP servers based on the handshakes.
RDP Security Check - Installation
neutron@kali[/kali]$ sudo cpan
Loading internal logger. Log::Log4perl recommended for better logging
CPAN.pm requires configuration, but most of it can be done automatically.
If you answer 'no' below, you will enter an interactive dialog for each
configuration option instead.
Would you like to configure as much as possible automatically? [yes] yes
Autoconfiguration complete.
commit: wrote '/root/.cpan/CPAN/MyConfig.pm'
You can re-run configuration any time with 'o conf init' in the CPAN shell
cpan shell -- CPAN exploration and modules installation (v2.27)
Enter 'h' for help.
cpan[1]> install Encoding::BER
Fetching with LWP:
http://www.cpan.org/authors/01mailrc.txt.gz
Reading '/root/.cpan/sources/authors/01mailrc.txt.gz'
............................................................................DONE
...SNIP...
RDP Security Check
neutron@kali[/kali]$ git clone https://github.com/CiscoCXSecurity/rdp-sec-check.git && cd rdp-sec-check
neutron@kali[/kali]$ ./rdp-sec-check.pl 10.129.201.248
Starting rdp-sec-check v0.9-beta ( http://labs.portcullis.co.uk/application/rdp-sec-check/ ) at Sun Nov 7 16:50:32 2021
[+] Scanning 1 hosts
Target: 10.129.201.248
IP: 10.129.201.248
Port: 3389
[+] Checking supported protocols
[-] Checking if RDP Security (PROTOCOL_RDP) is supported...Not supported - HYBRID_REQUIRED_BY_SERVER
[-] Checking if TLS Security (PROTOCOL_SSL) is supported...Not supported - HYBRID_REQUIRED_BY_SERVER
[-] Checking if CredSSP Security (PROTOCOL_HYBRID) is supported [uses NLA]...Supported
[+] Checking RDP Security Layer
[-] Checking RDP Security Layer with encryption ENCRYPTION_METHOD_NONE...Not supported
[-] Checking RDP Security Layer with encryption ENCRYPTION_METHOD_40BIT...Not supported
[-] Checking RDP Security Layer with encryption ENCRYPTION_METHOD_128BIT...Not supported
[-] Checking RDP Security Layer with encryption ENCRYPTION_METHOD_56BIT...Not supported
[-] Checking RDP Security Layer with encryption ENCRYPTION_METHOD_FIPS...Not supported
[+] Summary of protocol support
[-] 10.129.201.248:3389 supports PROTOCOL_SSL : FALSE
[-] 10.129.201.248:3389 supports PROTOCOL_HYBRID: TRUE
[-] 10.129.201.248:3389 supports PROTOCOL_RDP : FALSE
[+] Summary of RDP encryption support
[-] 10.129.201.248:3389 supports ENCRYPTION_METHOD_NONE : FALSE
[-] 10.129.201.248:3389 supports ENCRYPTION_METHOD_40BIT : FALSE
[-] 10.129.201.248:3389 supports ENCRYPTION_METHOD_128BIT : FALSE
[-] 10.129.201.248:3389 supports ENCRYPTION_METHOD_56BIT : FALSE
[-] 10.129.201.248:3389 supports ENCRYPTION_METHOD_FIPS : FALSE
[+] Summary of security issues
rdp-sec-check v0.9-beta completed at Sun Nov 7 16:50:33 2021
WinRM
The Windows Remote Management (WinRM) is a simple Windows integrated remote management protocol based on the command line. WinRM uses the Simple Object Access Protocol (SOAP) to establish connections to remote hosts and their applications. Therefore, WinRM must be explicitly enabled and configured starting with Windows 10. WinRM relies on TCP ports 5985 and 5986 for communication, with the last port 5986 using HTTPS, as ports 80 and 443 were previously used for this task.
Footprinting the Service
We will see that only HTTP (TCP 5985) is used instead of HTTPS (TCP 5986).
rmns@xyz[/xyz]$ nmap -sV -sC 10.129.201.248 -p5985,5986 --disable-arp-ping -n
Starting Nmap 7.92 ( https://nmap.org ) at 2021-11-06 16:31 CET
Nmap scan report for 10.129.201.248
Host is up (0.030s latency).
PORT STATE SERVICE VERSION
5985/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
|_http-title: Not Found
|_http-server-header: Microsoft-HTTPAPI/2.0
Service Info: OS: Windows; CPE: cpe:/o:microsoft:windows
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 7.34 seconds
If we want to find out whether one or more remote servers can be reached via WinRM, we can easily do this with the help of PowerShell. We can use the tool called evil-winrm
neutron@kali[/kali]$ evil-winrm -i 10.129.201.248 -u cryanight -p P455w0rD!
Evil-WinRM shell v3.3
Warning: Remote path completions is disabled due to ruby limitation: quoting_detection_proc() function is unimplemented on this machine
Data: For more information, check Evil-WinRM Github: https://github.com/Hackplayers/evil-winrm#Remote-path-completion
Info: Establishing connection to remote endpoint
*Evil-WinRM* PS C:\Users\cryanight\Documents>
WMI
Windows Management Instrumentation (WMI) is Microsoft's implementation and also an extension of the Common Information Model (CIM), core functionality of the standardized Web-Based Enterprise Management (WBEM) for the Windows platform. WMI allows read and write access to almost all settings on Windows systems. Understandably, this makes it the most critical interface in the Windows environment for the administration and remote maintenance of Windows computers, regardless of whether they are PCs or servers. WMI is typically accessed via PowerShell, VBScript, or the Windows Management Instrumentation Console (WMIC). WMI is not a single program but consists of several programs and various databases, also known as repositories.
Footprinting the Service
The initialization of the WMI communication always takes place on TCP port 135, and after the successful establishment of the connection, the communication is moved to a random port. For example, the program wmiexec.py from the Impacket toolkit can be used for this.
neutron@kali[/kali]$ /usr/share/doc/python3-impacket/examples/wmiexec.py cryanight:"P455w0rD!"@10.129.201.248 "hostname"
Impacket v0.9.22 - Copyright 2020 SecureAuth Corporation
[*] SMBv3.0 dialect used
ILF-SQL-01