Hacking Windows 95, Part 1
During a CTF game, we came across very-very old systems. Turns out, it is not that easy to hack those dinosaur old systems, because modern tools like Metasploit do not have sploits for those old boxes and of course our "133t h4cking skillz" are useless without Metasploit... :)
But I had an idea: This can be a pretty good small research for fun.
The rules for the hack are the following:
- Only publicly available tools can be used for this hack, so no tool development. This is a CTF for script bunniez, and we can't haz code!
- Only hacks without user interaction are allowed (IE based sploits are out of scope).
- I need instant remote code execution. For example, if I can drop a malware to the c: drive, and change autoexec.bat, I'm still not done, because no one will reboot the CTF machine in a real CTF for me. If I can reboot the machine, that's OK.
- I don't have physical access.
I have chosen Windows 95 for this task. First, I had to get a genuine Windows 95 installer, so I visited the Microsoft online shop and downloaded it from their official site.
I installed it in a virtualized environment (remember, you need a boot floppy to install from the CD), and it hit me with a serious nostalgia bomb after watching the installer screens. "Easier to use", "faster and more efficient", "high-powered performance", "friendly", "intuitive interface". Who does not want that? :)
Now that I have a working Windows 95 box, setting up the TCP/IP is easy, let's try to hack it!
My first tool is always nmap. Let's scan the box! Below I'm showing the interesting parts from the result:
PORT STATE SERVICE VERSION 139/tcp open netbios-ssn 137/udp open|filtered netbios-ns 138/udp open|filtered netbios-dgm Running: Microsoft Windows 3.X|95 OS details: Microsoft Windows for Workgroups 3.11 or Windows 95 TCP Sequence Prediction: Difficulty=25 (Good luck!) IP ID Sequence Generation: Broken little-endian incremental
The first exciting thing to note is that there is no port 445! Port 445 is only since NT 4.0. If you check all the famous windows sploits (e.g., MS03-026, MS08-067), all of them use port 445 and named pipes. But there are no named pipes on Windows 95!
Because I'm a Nessus monkey, let's run a free Nessus scan on it!
Only one critical vulnerability found:
Microsoft Windows NT 4.0 Unsupported Installation Detection
Thanks for nothing, Nessus! But at least it was for free.
Next, I tried GFI Languard, nothing. It detected the machine as Win95, the opened TCP port, and some UDP ports as open (false-positive), and that's all...
Let's try another free vulnerability scanner tool, Nexpose. The results are much better:
- CIFS NULL Session Permitted
- Weak LAN Manager hashing permitted
- SMB signing not required
- Windows 95/98/ME Share Level Password Bypass
- TCP Sequence Number Approximation Vulnerability
- ICMP netmask response
- CIFS Share Readable By Everyone
I think the following vulnerabilities are useless for me at the moment:
- Weak LAN Manager hashing permitted - without user interaction or services looking at the network, useless (I might be wrong here, will check this later)
- TCP Sequence Number Approximation Vulnerability - not interesting
- ICMP netmask response - not interesting
- CIFS Share Readable By Everyone - unless there is a password in a text file, useless
But we have two interesting vulns:
- CIFS NULL Session Permitted - this could be interesting, I will check this later ...
- Windows 95/98/ME Share Level Password Bypass - BINGO!
Let me quote Nexpose here:
"3.2.3 Windows 95/98/ME Share Level Password Bypass (CIFS-win9x-onebyte-password)
A flaw in the Windows 95/98/ME File and Print Sharing service allows unauthorized users to access file and print shares by sending the first character of the password. Due to the limited number of attempts required to guess the password, brute force attacks can be performed in just a few seconds.
Established connection to share TEST with password P."
The vulnerability description at MS side:
For example if the password is "Password" (without quotes) and the client sends the password "P" (without quotes) and the length of 1, the client is authenticated. To find the rest of the password, the attacker increments the length to 2 and starts guessing the second letter until he reaches "PA" and gets authenticated again. As share passwords in Windows 95 are not case sensitive, "Pa" and "PA" will also be accepted. The attacker can continue to increment the length and guessing the next letter one-by-one until he gets the full "PASSWORD" (as the maximum length is 8 characters).
I believe all characters between ALT+033 and ALT+255 can be used in the share password in Windows 95, but as it is case insensitive, we have 196 characters to use, and a maximum length of 8 characters. In worst case this means that we can guess the full password in 1568 requests. The funny thing is that the share password is not connected to (by default) any username/account, and it cannot be locked via brute force.
I believe all characters between ALT+033 and ALT+255 can be used in the share password in Windows 95, but as it is case insensitive, we have 196 characters to use, and a maximum length of 8 characters. In worst case this means that we can guess the full password in 1568 requests. The funny thing is that the share password is not connected to (by default) any username/account, and it cannot be locked via brute force.
Luckily there is a great tool which can exploit this vulnerability:
Let's check this tool in action:
W00t w00t, it brute forced the password in less then 2 seconds!
Looking at a wireshark dump we can see how it is done:
As you can see, in the middle of the dump we can see that it already guessed the part "PASS" and it is brute-forcing the fifth character, it founds that "W" is the correct fifth character, and starts brute-forcing the sixth character.
If we are lucky with the CTF, the whole C:\ drive is shared with full read-write access, and we can write our team identifier into the c:\flag.txt. But what if we want remote code execution? Stay tuned, this is going to be the topic of the next part of this post.
More info- Hacking Tools Free Download
- Hacker Tool Kit
- Hack Tools For Games
- Hacker Tools Online
- Hacking Tools For Windows 7
- Hacking Tools Pc
- Pentest Tools Port Scanner
- Hacker Tools 2019
- Hacker Security Tools
- Hacking Tools For Windows 7
- Hack Tools Mac
- Hacker Techniques Tools And Incident Handling
- Hacking Tools Github
- Pentest Tools Bluekeep
- Hacker Tools Apk Download
- Pentest Tools Apk
- Hack Tools Download
- Hacker Tools Apk
- Pentest Tools Find Subdomains
- Best Pentesting Tools 2018
- Hack Tools Download
- Pentest Tools Windows
- Pentest Tools Android
- Hacking Tools Usb
- Hack Tools For Windows
- What Is Hacking Tools
- Free Pentest Tools For Windows
- Hak5 Tools
- Hacking Tools Software
- Hacker
- What Is Hacking Tools
- Pentest Tools Download
- Hacking Tools Name
- Hacking Tools Software
- Android Hack Tools Github
- Android Hack Tools Github
- Hacker Tools For Mac
- Pentest Tools Find Subdomains
- Hak5 Tools
- Pentest Tools Android
- Hacking Tools 2020
- Hacking Tools For Pc
- Pentest Tools Android
- Hacker Tools Software
- Hacker Tool Kit
- Hacker Security Tools
- Pentest Tools Port Scanner
- Hacker Security Tools
- Easy Hack Tools
- Hacker Tools 2019
- Pentest Tools Nmap
- Hacker Tools
- Hacking Tools Mac
- Nsa Hacker Tools
- Pentest Tools Online
- New Hacker Tools
- Best Hacking Tools 2019
- Pentest Tools Url Fuzzer
- Growth Hacker Tools
- Pentest Tools Url Fuzzer
- Hack Tools 2019
- Android Hack Tools Github
- Hacker Security Tools
- Pentest Tools Linux
- Hack Tools For Mac
- Pentest Tools Github
- Hacking Tools For Windows Free Download
- Wifi Hacker Tools For Windows
- Hacking Tools And Software
- Hacker Tools 2020
- Tools 4 Hack
- Hacker Tools For Mac
- Pentest Tools Windows
- Pentest Tools For Mac
- Pentest Tools Download
- Pentest Tools Subdomain
- Free Pentest Tools For Windows
- Hacking Tools 2020
- Beginner Hacker Tools
- Hacking Tools Windows 10
- Pentest Tools Windows
- Easy Hack Tools
- Hacking Tools Name
- Pentest Tools Website
- Pentest Tools For Ubuntu
- Pentest Tools For Mac
- Best Hacking Tools 2020
- Pentest Tools Github
- Pentest Tools Framework
- World No 1 Hacker Software
- Hacking Tools 2020
- Pentest Tools Github
- Hacker Tools 2019
- Hacker Tools 2019
- Hacking Tools For Beginners
- Easy Hack Tools
- Hacking Tools For Windows 7
- Pentest Tools Website
- Hacking Tools For Mac
- Pentest Tools Port Scanner
- Pentest Tools Find Subdomains
- Usb Pentest Tools
- Hacking Tools Hardware
- Pentest Tools Url Fuzzer
- Hack Website Online Tool
- Ethical Hacker Tools
- Pentest Tools Apk
- Pentest Recon Tools
- Pentest Tools Windows
- Hacking Tools Hardware
- Hacking Tools Hardware
- Hacking Tools Pc
- Hacker Search Tools
- Hacking Tools
- Pentest Tools Find Subdomains
- Hacking Tools Free Download
- Pentest Tools Framework
- Black Hat Hacker Tools
- Hacker Tools 2020
- Pentest Tools Online
- Wifi Hacker Tools For Windows
- Install Pentest Tools Ubuntu
- Hacking Tools Kit
- Hack Tool Apk
- Pentest Tools Review
- Hackers Toolbox
- Pentest Tools Review
0 Comments:
Post a Comment
<< Home