Scanning for SMB Vulnerabilities with enum4linux
2023-10-16 00:35:21 Author: infosecwriteups.com(查看原文) 阅读量:36 收藏

Ahmet Talha Şen

InfoSec Write-ups

Created by lexica.art

In the world of ethical hacking and penetration testing, understanding the vulnerabilities of SMB (Server Message Block) services is crucial. SMB is a protocol that enables file and print sharing between systems, primarily on Windows networks. In this lab, we will use the enum4linux tool, a powerful SMB enumeration tool, to discover information about SMB services on target systems. This information can be vital for identifying potential vulnerabilities and strengthening network security. Let’s walk through the objectives step by step.

Step 1: Verify enum4linux Installation and View the Help File

  1. Access Kali Linux: First, log in to your Kali Linux virtual machine using the username kali and the password kali. Open a terminal session.
  2. Gain Root Access: Most enum4linux commands require root privileges. To obtain persistent root access, use the sudo su command.
┌──(kali㉿Kali)-[~]
└─$sudo su

3. View Help File: To understand enum4linux’s capabilities and syntax, access the help file using the enum4linux --help command.

┌──(root㉿Kali)-[~]
└─# enum4linux --help

The help file contains valuable information about the available options and the dependencies on Samba utilities.

Which Samba utilities does the help file indicate are used by the enum4linux tool?

The Samba utilities used by enum4linux are rpcclient, net, nmblookup, and smbclient.

Step 2: Research Terms Associated with SMB Functions

Understanding SMB-related terms is essential for interpreting enum4linux output effectively. Here are some terms and their definitions:

  • Relative Identifier (RID): Uniquely identifies a user, group, system, or domain.
  • Security Identifier (SID): Uniquely identifies users and groups within the local domain and can work globally between domains.
  • Domain Controller (DC): Manages network and identity security requests, authenticates users, and controls access to IT resources.
  • Lightweight Directory Access Protocol (LDAP): A directory access protocol enabling communication for services and clients using LDAP naming services.
  • Workgroup: A group of standalone computers administered independently.

Step 1: Scan Virtual Networks to Find Potential Targets

Identifying potential SMB targets involves scanning open ports. Common ports associated with SMB services include:

  • TCP 135: RPC
  • TCP 139: NetBIOS Session
  • TCP 389: LDAP Server
  • TCP 445: SMB File Service
  • TCP 9389: Active Directory Web Services
  • TCP/UDP 137: NetBIOS Name Service
  • UDP 138: NetBIOS Datagram
  1. Scan 172.17.0.0 Virtual Network: Use the nmap -sN command to find services on hosts in the 172.17.0.0 virtual network.
┌──(root㉿Kali)-[~]
└─# nmap -sN 172.17.0.0/24
Starting Nmap 7.94 ( https://nmap.org ) at 2023-10-03 12:10 UTC
Nmap scan report for metasploitable.vm (172.17.0.2)
Host is up (0.000010s latency).
Not shown: 983 closed tcp ports (reset)
PORT STATE SERVICE
21/tcp open|filtered ftp
22/tcp open|filtered ssh
23/tcp open|filtered telnet
25/tcp open|filtered smtp
80/tcp open|filtered http
111/tcp open|filtered rpcbind
139/tcp open|filtered netbios-ssn
445/tcp open|filtered microsoft-ds
512/tcp open|filtered exec
513/tcp open|filtered login
514/tcp open|filtered shell
1099/tcp open|filtered rmiregistry
1524/tcp open|filtered ingreslock
2121/tcp open|filtered ccproxy-ftp
3306/tcp open|filtered mysql
5432/tcp open|filtered postgresql
6667/tcp open|filtered irc
MAC Address: 02:42:AC:11:00:02 (Unknown)

Nmap scan report for 172.17.0.1 (172.17.0.1)
Host is up (0.000010s latency).
Not shown: 999 closed tcp ports (reset)
PORT STATE SERVICE
22/tcp open|filtered ssh

Nmap done: 256 IP addresses (2 hosts up) scanned in 4.60 seconds

What does Nmap reveal about hosts on the 172.17.0.0/24 network?

Only one host is present, identified as 172.17.0.2.

What ports are open on the host that identify running SMB services? What does Nmap call these services?

The open ports on the host 172.17.0.2 are TCP 139 (netbios-ssn) and TCP 445 (microsoft-ds).

2. Scan 10.6.6.0/24 Subnet: Perform a nmap -sN scan on the 10.6.6.0/24 subnet.

┌──(root㉿Kali)-[~]
└─# nmap -sN 10.6.6.0/24
Starting Nmap 7.94 ( https://nmap.org ) at 2023-10-03 12:10 UTC
Nmap scan report for webgoat.vm (10.6.6.11)
Host is up (0.000010s latency).
Not shown: 997 closed tcp ports (reset)
PORT STATE SERVICE
8080/tcp open|filtered http-proxy
8888/tcp open|filtered sun-answerbook
9001/tcp open|filtered tor-orport
MAC Address: 02:42:0A:06:06:0B (Unknown)

Nmap scan report for juice-shop.vm (10.6.6.12)
Host is up (0.000011s latency).
Not shown: 999 closed tcp ports (reset)
PORT STATE SERVICE
3000/tcp open|filtered ppp
MAC Address: 02:42:0A:06:06:0C (Unknown)

Nmap scan report for dvwa.vm (10.6.6.13)
Host is up (0.000011s latency).
Not shown: 999 closed tcp ports (reset)
PORT STATE SERVICE
80/tcp open|filtered http
MAC Address: 02:42:0A:06:06:0D (Unknown)

Nmap scan report for mutillidae.vm (10.6.6.14)
Host is up (0.000011s latency).
Not shown: 998 closed tcp ports (reset)
PORT STATE SERVICE
80/tcp open|filtered http
3306/tcp open|filtered mysql
MAC Address: 02:42:0A:06:06:0E (Unknown)

Nmap scan report for gravemind.vm (10.6.6.23)
Host is up (0.000011s latency).
Not shown: 994 closed tcp ports (reset)
PORT STATE SERVICE
21/tcp open|filtered ftp
22/tcp open|filtered ssh
53/tcp open|filtered domain
80/tcp open|filtered http
139/tcp open|filtered netbios-ssn
445/tcp open|filtered microsoft-ds
MAC Address: 02:42:0A:06:06:17 (Unknown)

Nmap scan report for 10.6.6.100 (10.6.6.100)
Host is up (0.000011s latency).
All 1000 scanned ports on 10.6.6.100 (10.6.6.100) are in ignored states.
Not shown: 1000 closed tcp ports (reset)
MAC Address: 02:42:0A:06:06:64 (Unknown)

Nmap scan report for 10.6.6.1 (10.6.6.1)
Host is up (0.000011s latency).
Not shown: 999 closed tcp ports (reset)
PORT STATE SERVICE
22/tcp open|filtered ssh

Nmap done: 256 IP addresses (7 hosts up) scanned in 4.70 seconds

Are there any potential target computers on this subnet running SMB services? Which computer or computers? How do you know?

Yes, the computer at 10.6.6.23 is a potential target. It has ports 139 and 445 open, indicating SMB services.

In this section, we will use enum4linux to gather more information about potential targets.

Step 1: Perform enum4linux Scan on Target 172.17.0.2

  1. Enumerate Users: Use the enum4linux -U option to list the users configured on the target 172.17.0.2. Remember to run enum4linux commands with root permissions.
┌──(root㉿Kali)-[~]
└─# enum4linux -U 172.17.0.2
Starting enum4linux v0.9.1 ( http://labs.portcullis.co.uk/application/enum4linux/ ) on Tue Oct 3 12:11:50 2023

=========================================( Target Information )=========================================

Target ........... 172.17.0.2
RID Range ........ 500-550,1000-1050
Username ......... ''
Password ......... ''
Known Usernames .. administrator, guest, krbtgt, domain admins, root, bin, none

=============================( Enumerating Workgroup/Domain on 172.17.0.2 )=============================

[+] Got domain/workgroup name: WORKGROUP

====================================( Session Check on 172.17.0.2 )====================================

[+] Server 172.17.0.2 allows sessions using username '', password ''

=================================( Getting domain SID for 172.17.0.2 )=================================

Domain Name: WORKGROUP
Domain Sid: (NULL SID)

[+] Can't determine if host is part of domain or part of a workgroup

========================================( Users on 172.17.0.2 )========================================

index: 0x1 RID: 0x3f2 acb: 0x00000011 Account: games Name: games Desc: (null)
index: 0x2 RID: 0x1f5 acb: 0x00000011 Account: nobody Name: nobody Desc: (null)
index: 0x3 RID: 0x4ba acb: 0x00000011 Account: bind Name: (null) Desc: (null)
index: 0x4 RID: 0x402 acb: 0x00000011 Account: proxy Name: proxy Desc: (null)
index: 0x5 RID: 0x4b4 acb: 0x00000011 Account: syslog Name: (null) Desc: (null)
index: 0x6 RID: 0xbba acb: 0x00000010 Account: user Name: just a user,111,, Desc: (null)
index: 0x7 RID: 0x42a acb: 0x00000011 Account: www-data Name: www-data Desc: (null)
index: 0x8 RID: 0x3e8 acb: 0x00000011 Account: root Name: root Desc: (null)
index: 0x9 RID: 0x3fa acb: 0x00000011 Account: news Name: news Desc: (null)
index: 0xa RID: 0x4c0 acb: 0x00000011 Account: postgres Name: PostgreSQL administrator,,, Desc: (null)
index: 0xb RID: 0x3ec acb: 0x00000011 Account: bin Name: bin Desc: (null)
index: 0xc RID: 0x3f8 acb: 0x00000011 Account: mail Name: mail Desc: (null)
index: 0xd RID: 0x4c6 acb: 0x00000011 Account: distccd Name: (null) Desc: (null)
index: 0xe RID: 0x4ca acb: 0x00000011 Account: proftpd Name: (null) Desc: (null)
index: 0xf RID: 0x4b2 acb: 0x00000011 Account: dhcp Name: (null) Desc: (null)
index: 0x10 RID: 0x3ea acb: 0x00000011 Account: daemon Name: daemon Desc: (null)
index: 0x11 RID: 0x4b8 acb: 0x00000011 Account: sshd Name: (null) Desc: (null)
index: 0x12 RID: 0x3f4 acb: 0x00000011 Account: man Name: man Desc: (null)
index: 0x13 RID: 0x3f6 acb: 0x00000011 Account: lp Name: lp Desc: (null)
index: 0x14 RID: 0x4c2 acb: 0x00000011 Account: mysql Name: MySQL Server,,, Desc: (null)
index: 0x15 RID: 0x43a acb: 0x00000011 Account: gnats Name: Gnats Bug-Reporting System (admin)Desc: (null)
index: 0x16 RID: 0x4b0 acb: 0x00000011 Account: libuuid Name: (null) Desc: (null)
index: 0x17 RID: 0x42c acb: 0x00000011 Account: backup Name: backup Desc: (null)
index: 0x18 RID: 0xbb8 acb: 0x00000010 Account: msfadmin Name: msfadmin,,, Desc: (null)
index: 0x19 RID: 0x4c8 acb: 0x00000011 Account: telnetd Name: (null) Desc: (null)
index: 0x1a RID: 0x3ee acb: 0x00000011 Account: sys Name: sys Desc: (null)
index: 0x1b RID: 0x4b6 acb: 0x00000011 Account: klog Name: (null) Desc: (null)
index: 0x1c RID: 0x4bc acb: 0x00000011 Account: postfix Name: (null) Desc: (null)
index: 0x1d RID: 0xbbc acb: 0x00000011 Account: service Name: ,,, Desc: (null)
index: 0x1e RID: 0x434 acb: 0x00000011 Account: list Name: Mailing List Manager Desc: (null)
index: 0x1f RID: 0x436 acb: 0x00000011 Account: irc Name: ircd Desc: (null)
index: 0x20 RID: 0x4be acb: 0x00000011 Account: ftp Name: (null) Desc: (null)
index: 0x21 RID: 0x4c4 acb: 0x00000011 Account: tomcat55 Name: (null) Desc: (null)
index: 0x22 RID: 0x3f0 acb: 0x00000011 Account: sync Name: sync Desc: (null)
index: 0x23 RID: 0x3fc acb: 0x00000011 Account: uucp Name: uucp Desc: (null)

user:[games] rid:[0x3f2]
user:[nobody] rid:[0x1f5]
user:[bind] rid:[0x4ba]
user:[proxy] rid:[0x402]
user:[syslog] rid:[0x4b4]
user:[user] rid:[0xbba]
user:[www-data] rid:[0x42a]
user:[root] rid:[0x3e8]
user:[news] rid:[0x3fa]
user:[postgres] rid:[0x4c0]
user:[bin] rid:[0x3ec]
user:[mail] rid:[0x3f8]
user:[distccd] rid:[0x4c6]
user:[proftpd] rid:[0x4ca]
user:[dhcp] rid:[0x4b2]
user:[daemon] rid:[0x3ea]
user:[sshd] rid:[0x4b8]
user:[man] rid:[0x3f4]
user:[lp] rid:[0x3f6]
user:[mysql] rid:[0x4c2]
user:[gnats] rid:[0x43a]
user:[libuuid] rid:[0x4b0]
user:[backup] rid:[0x42c]
user:[msfadmin] rid:[0xbb8]
user:[telnetd] rid:[0x4c8]
user:[sys] rid:[0x3ee]
user:[klog] rid:[0x4b6]
user:[postfix] rid:[0x4bc]
user:[service] rid:[0xbbc]
user:[list] rid:[0x434]
user:[irc] rid:[0x436]
user:[ftp] rid:[0x4be]
user:[tomcat55] rid:[0x4c4]
user:[sync] rid:[0x3f0]
user:[uucp] rid:[0x3fc]
enum4linux complete on Tue Oct 3 12:11:51 2023

Enum4linux aggregates output from multiple Samba tools to provide concise results. If needed, you can use the verbose option -v to see how each feature is used.

2. List File Shares: Enumerate file shares on 172.17.0.2 using enum4linux -S. Use the verbose option v to understand which Samba tools are used.

┌──(root㉿Kali)-[~]
└─# enum4linux -Sv 172.17.0.2

[V] Dependent program "nmblookup" found in /usr/bin/nmblookup

[V] Dependent program "net" found in /usr/bin/net

[V] Dependent program "rpcclient" found in /usr/bin/rpcclient

[V] Dependent program "smbclient" found in /usr/bin/smbclient

[V] Dependent program "polenum" found in /usr/bin/polenum

[V] Dependent program "ldapsearch" found in /usr/bin/ldapsearch

Starting enum4linux v0.9.1 ( http://labs.portcullis.co.uk/application/enum4linux/ ) on Tue Oct 3 12:12:48 2023

=========================================( Target Information )=========================================

Target ........... 172.17.0.2
RID Range ........ 500-550,1000-1050
Username ......... ''
Password ......... ''
Known Usernames .. administrator, guest, krbtgt, domain admins, root, bin, none

=============================( Enumerating Workgroup/Domain on 172.17.0.2 )=============================

[V] Attempting to get domain name with command: nmblookup -A '172.17.0.2'

[+] Got domain/workgroup name: WORKGROUP

====================================( Session Check on 172.17.0.2 )====================================

[V] Attempting to make null session using command: smbclient -W 'WORKGROUP' //'172.17.0.2'/ipc$ -U''%'' -c 'help' 2>&1

[+] Server 172.17.0.2 allows sessions using username '', password ''

=================================( Getting domain SID for 172.17.0.2 )=================================

[V] Attempting to get domain SID with command: rpcclient -W 'WORKGROUP' -U''%'' 172.17.0.2 -c 'lsaquery' 2>&1

Domain Name: WORKGROUP
Domain Sid: (NULL SID)

[+] Can't determine if host is part of domain or part of a workgroup

==================================( Share Enumeration on 172.17.0.2 )==================================

[V] Attempting to get share list using authentication

Sharename Type Comment
--------- ---- -------
print$ Disk Printer Drivers
tmp Disk oh noes!
opt Disk
IPC$ IPC IPC Service (metasploitable server (Samba 3.0.20-Debian))
ADMIN$ IPC IPC Service (metasploitable server (Samba 3.0.20-Debian))
Reconnecting with SMB1 for workgroup listing.

Server Comment
--------- -------

Workgroup Master
--------- -------
WORKGROUP METASPLOITABLE

[+] Attempting to map shares on 172.17.0.2

[V] Attempting map to share //172.17.0.2/print$ with command: smbclient -W 'WORKGROUP' //'172.17.0.2'/'print$' -U''%'' -c dir 2>&1

//172.17.0.2/print$ Mapping: DENIED Listing: N/A Writing: N/A

[V] Attempting map to share //172.17.0.2/tmp with command: smbclient -W 'WORKGROUP' //'172.17.0.2'/'tmp' -U''%'' -c dir 2>&1

//172.17.0.2/tmp Mapping: OK Listing: OK Writing: N/A

[V] Attempting map to share //172.17.0.2/opt with command: smbclient -W 'WORKGROUP' //'172.17.0.2'/'opt' -U''%'' -c dir 2>&1

//172.17.0.2/opt Mapping: DENIED Listing: N/A Writing: N/A

[V] Attempting map to share //172.17.0.2/IPC$ with command: smbclient -W 'WORKGROUP' //'172.17.0.2'/'IPC$' -U''%'' -c dir 2>&1

[E] Can't understand response:

NT_STATUS_NETWORK_ACCESS_DENIED listing \*
//172.17.0.2/IPC$ Mapping: N/A Listing: N/A Writing: N/A

[V] Attempting map to share //172.17.0.2/ADMIN$ with command: smbclient -W 'WORKGROUP' //'172.17.0.2'/'ADMIN$' -U''%'' -c dir 2>&1

//172.17.0.2/ADMIN$ Mapping: DENIED Listing: N/A Writing: N/A
enum4linux complete on Tue Oct 3 12:12:48 2023

Which Samba tool was used to map the file shares?

The Samba tool used to map file shares is smbclient.

How many file shares are listed for target 172.17.0.2? What does the $ indicate at the end of the share name?

There are five file shares listed for 172.17.0.2. The $ at the end of the share name indicates hidden shares.

3. List Password Policies: To understand the password policies on the target system, use the enum4linux -P command.

┌──(root㉿Kali)-[~]
└─# enum4linux -P 172.17.0.2
Starting enum4linux v0.9.1 ( http://labs.portcullis.co.uk/application/enum4linux/ ) on Tue Oct 3 12:13:44 2023

=========================================( Target Information )=========================================

Target ........... 172.17.0.2
RID Range ........ 500-550,1000-1050
Username ......... ''
Password ......... ''
Known Usernames .. administrator, guest, krbtgt, domain admins, root, bin, none

=============================( Enumerating Workgroup/Domain on 172.17.0.2 )=============================

[+] Got domain/workgroup name: WORKGROUP

====================================( Session Check on 172.17.0.2 )====================================

[+] Server 172.17.0.2 allows sessions using username '', password ''

=================================( Getting domain SID for 172.17.0.2 )=================================

Domain Name: WORKGROUP
Domain Sid: (NULL SID)

[+] Can't determine if host is part of domain or part of a workgroup

=============================( Password Policy Information for 172.17.0.2 )=============================

[+] Attaching to 172.17.0.2 using a NULL share

[+] Trying protocol 139/SMB...

[+] Found domain(s):

[+] METASPLOITABLE
[+] Builtin

[+] Password Info for Domain: METASPLOITABLE

[+] Minimum password length: 5
[+] Password history length: None
[+] Maximum password age: Not Set
[+] Password Complexity Flags: 000000

[+] Domain Refuse Password Change: 0
[+] Domain Password Store Cleartext: 0
[+] Domain Password Lockout Admins: 0
[+] Domain Password No Clear Change: 0
[+] Domain Password No Anon Change: 0
[+] Domain Password Complex: 0

[+] Minimum password age: None
[+] Reset Account Lockout Counter: 30 minutes
[+] Locked Account Duration: 30 minutes
[+] Account Lockout Threshold: None
[+] Forced Log off Time: Not Set

[+] Retieved partial password policy with rpcclient:

Password Complexity: Disabled
Minimum Password Length: 0

enum4linux complete on Tue Oct 3 12:13:46 2023

What is the minimum password length set for accounts on this server? What is the account lockout threshold setting?

The minimum password length is five characters, and no account lockout threshold is set.

How would you rate the security of the password policy set for this domain? Low, medium, or high? Explain.

The security of the password policy is low. The minimum password length is too short, and the password complexity flag is 000000, indicating no password complexity policy is set. Additionally, there is no minimum password age configured.

Step 2: Perform Simple Enumeration Scan on Target 10.6.6.23

  1. Combine Enumeration Options: Enum4linux has an option to combine multiple enumeration operations into one command using the a argument. This allows quick enumeration of SMB information.
┌──(root㉿Kali)-[~]
└─# enum4linux -a 10.6.6.23
Starting enum4linux v0.9.1 ( http://labs.portcullis.co.uk/application/enum4linux/ ) on Tue Oct 3 12:14:24 2023

=========================================( Target Information )=========================================

Target ........... 10.6.6.23
RID Range ........ 500-550,1000-1050
Username ......... ''
Password ......... ''
Known Usernames .. administrator, guest, krbtgt, domain admins, root, bin, none

=============================( Enumerating Workgroup/Domain on 10.6.6.23 )=============================

[E] Can't find workgroup/domain

=================================( Nbtstat Information for 10.6.6.23 )=================================

Looking up status of 10.6.6.23
No reply from 10.6.6.23

=====================================( Session Check on 10.6.6.23 )=====================================

[+] Server 10.6.6.23 allows sessions using username '', password ''

==================================( Getting domain SID for 10.6.6.23 )==================================

Domain Name: WORKGROUP
Domain Sid: (NULL SID)

[+] Can't determine if host is part of domain or part of a workgroup

====================================( OS information on 10.6.6.23 )====================================

[E] Can't get OS info with smbclient

[+] Got OS info for 10.6.6.23 from srvinfo:
GRAVEMIND Wk Sv PrQ Unx NT SNT Samba 4.9.5-Debian
platform_id : 500
os version : 6.1
server type : 0x809a03

=========================================( Users on 10.6.6.23 )=========================================

index: 0x1 RID: 0x3e8 acb: 0x00000015 Account: masterchief Name: Desc:
index: 0x2 RID: 0x3e9 acb: 0x00000015 Account: arbiter Name: Desc:

user:[masterchief] rid:[0x3e8]
user:[arbiter] rid:[0x3e9]

===================================( Share Enumeration on 10.6.6.23 )===================================

Sharename Type Comment
--------- ---- -------
homes Disk All home directories
workfiles Disk Confidential Workfiles
print$ Disk Printer Drivers
IPC$ IPC IPC Service (Samba 4.9.5-Debian)
Reconnecting with SMB1 for workgroup listing.

Server Comment
--------- -------

Workgroup Master
--------- -------

[+] Attempting to map shares on 10.6.6.23

[E] Can't understand response:

tree connect failed: NT_STATUS_BAD_NETWORK_NAME
//10.6.6.23/homes Mapping: N/A Listing: N/A Writing: N/A
//10.6.6.23/workfiles Mapping: OK Listing: OK Writing: N/A
//10.6.6.23/print$ Mapping: OK Listing: OK Writing: N/A

[E] Can't understand response:

NT_STATUS_OBJECT_NAME_NOT_FOUND listing \*
//10.6.6.23/IPC$ Mapping: N/A Listing: N/A Writing: N/A

=============================( Password Policy Information for 10.6.6.23 )=============================

[+] Attaching to 10.6.6.23 using a NULL share

[+] Trying protocol 139/SMB...

[+] Found domain(s):

[+] GRAVEMIND
[+] Builtin

[+] Password Info for Domain: GRAVEMIND

[+] Minimum password length: 5
[+] Password history length: None
[+] Maximum password age: 37 days 6 hours 21 minutes
[+] Password Complexity Flags: 000000

[+] Domain Refuse Password Change: 0
[+] Domain Password Store Cleartext: 0
[+] Domain Password Lockout Admins: 0
[+] Domain Password No Clear Change: 0
[+] Domain Password No Anon Change: 0
[+] Domain Password Complex: 0

[+] Minimum password age: None
[+] Reset Account Lockout Counter: 30 minutes
[+] Locked Account Duration: 30 minutes
[+] Account Lockout Threshold: None
[+] Forced Log off Time: 37 days 6 hours 21 minutes

[+] Retieved partial password policy with rpcclient:

Password Complexity: Disabled
Minimum Password Length: 5

========================================( Groups on 10.6.6.23 )========================================

[+] Getting builtin groups:

[+] Getting builtin group memberships:

[+] Getting local groups:

[+] Getting local group memberships:

[+] Getting domain groups:

[+] Getting domain group memberships:

====================( Users on 10.6.6.23 via RID cycling (RIDS: 500-550,1000-1050) )====================

[I] Found new SID:
S-1-22-1

[I] Found new SID:
S-1-5-32

[I] Found new SID:
S-1-5-32

[I] Found new SID:
S-1-5-32

[I] Found new SID:
S-1-5-32

[+] Enumerating users using SID S-1-22-1 and logon username '', password ''

S-1-22-1-1000 Unix User\masterchief (Local User)
S-1-22-1-1001 Unix User\arbiter (Local User)
S-1-22-1-1002 Unix User\labuser (Local User)

[+] Enumerating users using SID S-1-5-32 and logon username '', password ''

S-1-5-32-544 BUILTIN\Administrators (Local Group)
S-1-5-32-545 BUILTIN\Users (Local Group)
S-1-5-32-546 BUILTIN\Guests (Local Group)
S-1-5-32-547 BUILTIN\Power Users (Local Group)
S-1-5-32-548 BUILTIN\Account Operators (Local Group)
S-1-5-32-549 BUILTIN\Server Operators (Local Group)
S-1-5-32-550 BUILTIN\Print Operators (Local Group)

[+] Enumerating users using SID S-1-5-21-3080196717-3701805971-2094628062 and logon username '', password ''

S-1-5-21-3080196717-3701805971-2094628062-501 GRAVEMIND\nobody (Local User)
S-1-5-21-3080196717-3701805971-2094628062-513 GRAVEMIND\None (Domain Group)
S-1-5-21-3080196717-3701805971-2094628062-1000 GRAVEMIND\masterchief (Local User)
S-1-5-21-3080196717-3701805971-2094628062-1001 GRAVEMIND\arbiter (Local User)

=================================( Getting printer info for 10.6.6.23 )=================================

No printers returned.

enum4linux complete on Tue Oct 3 12:15:16 2023

How many local users and groups are there on target 10.6.6.23?

There are 3 local users and 7 groups on target 10.6.6.23.

What are the shares located on this target?

The shares on this target are “homes,” “workfiles,” and “print$.” Note that “IPC$” is for the server process itself and is created by default.

Smbclient is a valuable tool for transferring files between systems, similar to an FTP client. We will use smbclient to transfer a file to the target system at 172.17.0.2 as a simulated malware exploit.

  1. Create a Text File: Use the cat command to create a text file named badfile.txt with desired content. For example:
cat >> badfile.txt
This is a bad file.
Press CTRL-C to write the file.

Press CTRL-C when done.

2. Explore smbclient Options: Check smbclient options using the smbclient --help command.

smbclient --help

3. List Shares on Target: List shares on the target host (172.17.0.2) using the smbclient -L command.

┌──(root㉿Kali)-[~]
└─# smbclient -L //172.17.0.2/
Password for [WORKGROUP\root]:
Anonymous login successful

Sharename Type Comment
--------- ---- -------
print$ Disk Printer Drivers
tmp Disk oh noes!
opt Disk
IPC$ IPC IPC Service (metasploitable server (Samba 3.0.20-Debian))
ADMIN$ IPC IPC Service (metasploitable server (Samba 3.0.20-Debian))
Reconnecting with SMB1 for workgroup listing.
Anonymous login successful

Server Comment
--------- -------

Workgroup Master
--------- -------
WORKGROUP METASPLOITABLE

4. Connect to a Share: Connect to the tmp share on the target using smbclient.

┌──(root㉿Kali)-[~]
└─# smbclient //172.17.0.2/tmp
Password for [WORKGROUP\root]:
Anonymous login successful
Try "help" to get a list of possible commands.
smb: \>

5. Explore smbclient Commands: Once connected, you can explore available commands by typing help.

6. Upload a File: Upload the badfile.txt to the target server using the put command.

put badfile.txt badfile.txt

This transfers the file to the target server.

7. Verify Upload: Use the dir command to verify that the file was successfully uploaded.

dir

8. Exit smbclient: Type quit to exit smbclient and return to the command prompt.

Imagine you are conducting a penetration test on a client’s network. You have gained access to an internal network by exploiting a vulnerability in an ad hoc web server outside the firewall. Now, you want to send a dummy malware file to hosts on the network as part of the penetration test.

Here are the steps you would follow:

  1. Identify Vulnerable Hosts: Scan the internal network using tools like Nmap to identify hosts with open SMB ports (139 and 445) that make them potential targets.
  2. Enumerate Target Systems: Use enum4linux to enumerate user accounts, groups, shares, and password policies on the identified hosts. This information helps assess the potential attack surface.
  3. Select a Target: Choose a target host based on the vulnerabilities discovered during enumeration. Consider factors such as weak passwords or accessible shares.
  4. Craft the Malware: Create a dummy malware file or payload that simulates an attack. Ensure it is harmless but indicative of a potential threat.
  5. Transfer the Malware: Use smbclient to upload the malware file to the selected target’s accessible share. This mimics an attacker exploiting an SMB vulnerability to deliver malware.
  6. Monitor for Detection: Continuously monitor the network for any security alerts or detection attempts. This helps assess the network’s security posture and incident response capabilities.
  7. Report Findings: After completing the penetration test, compile a detailed report of findings, vulnerabilities, and recommendations for remediation. Provide evidence of successful exploitation without causing harm.

Remember that penetration testing should always be conducted within the bounds of legal and ethical guidelines, with proper authorization from the client. The objective is to help organizations identify and address security weaknesses to improve overall network security.

This report documents the practical exercises conducted as part of the CISCO Ethical Hacker course, specifically focusing on using the enum4linux tool to address SMB vulnerabilities. All activities described were performed in a controlled, authorized environment, adhering to ethical hacking guidelines and legal regulations.


文章来源: https://infosecwriteups.com/scanning-for-smb-vulnerabilities-with-enum4linux-896f76d0c078?source=rss----7b722bfd1b8d---4
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