الأحد، 28 مايو 2023

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:
  1. 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!
  2. Only hacks without user interaction are allowed (IE based sploits are out of scope).
  3. 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.
  4. 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.

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.

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TOP ANDROID HACKING TOOLS OF 2018

An Android remote administration tool (RAT) is a programmed tool that allows a remote device to control a smartphone as if they have physical access to that system. While screen sharing and remote administration have many legal uses, "RAT" software is usually associated with the unauthorized or malicious activity. I have streamlined here top android hacking tools of 2018.

TOP ANDROID HACKING TOOLS OF 2018

Here are the most advanced in functionality top android hacking tools of 2018.

1. DROIDJACK

DroidJack gives you the power to establish control over your beloveds' Android devices with an easy to use GUI and all the features you need to monitor them. It has many advanced features that you can perform over the remote smartphone. DroidJack is one of the top lists as it also has the functionality to read/write WhatsApp messages.

You can also follow a step by step tutorial on how to hack smartphone remotely using droidjack.

2. OMNIRAT

OmniRAT is the super powerful multi-OS remote administration tool that can a smartphone either using a smartphone or using a Windows or Mac PC. It has a huge list of features that make it very powerful. It can make calls through that smartphone remotely. It's completely fully undetectable.

3. ANDRORAT

AndroRat is a client/server application developed in Java Android for the client side and in Java/Swing for the Server. The name AndroRat is a mix of Android and RAT (Remote Access Tool). It was developed as a project by the university students, which works great for hacking into Android devices.

You can also follow a step by step tutorial on how to hacking a smartphone remotely using androrat.

4. SPYNOTE

SpyNote is a lightweight Android remote administration tool (RAT) to hack into a smartphone device remotely. It gives you the power to establish control over Android devices with an easy to use GUI and all the features you need to monitor them. Build a custom APK or bind the payload to an already existing APK such as a game or social media app.

You can also follow a step by step tutorial on how to hack any android phone remotely with spynote.

5. AHMYTH

AhMyth is a powerful android remote administrator tool that gives you the power to establish control over your beloveds' android devices with an easy to use GUI and all the features you need to monitor them.

These are all the top android hacking tools of 2018. There are also many other rats but these are the most advanced in tech and features. There may appear few more that can compete these and make a place to be in the top android list.
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One Reason Why InfoSec Sucked In The Past 20 Years - The "Security Tips" Myth

From time to time, I get disappointed how much effort and money is put into securing computers, networks, mobile phones, ... and yet in 2016 here we are, where not much has changed on the defensive side. There are many things I personally blame for this situation, and one of them is the security tips.

The goal of these security tips is that if the average user follows these easy to remember rules, their computer will be safe. Unfortunately, by the time people integrate these rules into their daily life, these rules either become outdated, or these rules were so oversimplified that it was never true in the first place. Some of these security tips might sound ridiculous to people in InfoSec nowadays, but this is exactly what people still remember because we told them so for years.

PDF is safe to open

This is an oldie. I think this started at the time of macro viruses. Still, people think opening a PDF from an untrusted source is safer than opening a Word file. For details why this is not true, check: https://www.cvedetails.com/vulnerability-list/vendor_id-53/product_id-497/Adobe-Acrobat-Reader.html
On an unrelated note, people still believe PDF is integrity protected because the content cannot be changed (compared to a Word document).
Image stolen from Kaspersky

Java is secure

One of the best ones. Oracle started marketing Java as a safe language, where buffer overflows, format strings and pointer-based vulnerabilities are gone. Unfortunately, they forgot to tell the world that instead of "unsafe programs developed by others" they installed their unsafe program on 3 billion devices. 

Stay away from rogue websites and you will be safe

This is a very common belief I hear from average people. "I only visit some trusted news sites and social media, I never visit those shady sites." I have some bad news. At the time of malvertising and infected websites, you don't have to visit those shady sites anymore to get infected.

Don't use open WiFi

I have a very long explanation of why this makes no sense, see here. Actually, the whole recommendation makes no sense as people will connect to public WiFis, no matter what we (InfoSec) recommend.

The password policy nightmare

Actually, this topic has been covered by myself in two blog posts, see here and here. Long story short: use a password manager and 2-factor authentication wherever possible. Let the password manager choose the password for you. And last but not least, corporate password policy sux.

Sites with a padlock are safe

We tell people for years that the communication with HTTPS sites are safe, and you can be sure it is HTTPS by finding a randomly changing padlock icon somewhere next to the URL. What people hear is that sites with padlocks are safe. Whatever that means. The same goes for WiFi - a network with a padlock is safe.

Use Linux, it is free from malware

For years people told to Windows users that only if they would use Linux they won't have so much malware. Thanks to Android, now everyone in the world can enjoy malware on his/her Linux machine.

OSX is free from malware

It is true that there is significantly less malware on OSX than on Windows, but this is an "economical" question rather than a "security" one. The more people use OSX, the better target it will become. Some people even believe they are safe from phishing because they are using a Mac!

Updated AV + firewall makes me 100% safe

There is no such thing as 100% safe, and unfortunately, nowadays most malware is written for PROFIT, which means it can bypass these basic protections for days (or weeks, months, years). The more proactive protection is built into the product, the better!

How to backup data

Although this is one of the most important security tips which is not followed by people, my problem here is not the backup data advise, but how we as a community failed to provide easy to use ways to do that. Now that crypto-ransomware is a real threat to every Windows (and some OSX) users, even those people who have backups on their NAS can find their backups lost. The only hope is that at least OSX has Time Machine which is not targeted yet, and the only backup solution which really works.
The worst part is that we even created NAS devices which can be infected via worms ...

Disconnect your computer from the Internet when not used

There is no need to comment on this. Whoever recommends things like that, clearly has a problem.

Use (free) VPN to protect your anonimity

First of all. There is no such thing as free service. If it is free, you are the service. On another hand, a non-free VPN can introduce new vulnerablities, and they won't protect your anonymity. It replaces one ISP with another (your VPN provider). Even TOR cannot guarantee anonymity by itself, and VPNs are much worse.

The corporate "security tips" myth

"Luckily" these toxic security tips have infected the enterprise environment as well, not just the home users.

Use robots.txt to hide secret information on public websites

It is 2016 and somehow web developers still believe in this nonsense. And this is why this is usually the first to check on a website for penetration testers or attackers.

My password policy is safer than ever

As previously discussed, passwords are bad. Very bad. And they will stick with us for decades ...

Use WAF, IDS, IPS, Nextgen APT detection hibber-gibber and you will be safe

Companies should invest more in people and less into magic blinking devices.

Instead of shipping computers with bloatware, ship computers with exploit protection software
Teach people how to use a password safe
Teach people how to use 2FA
Teach people how to use common-sense

Conclusion

Computer security is complex, hard and the risks change every year. Is this our fault? Probably. But these kinds of security tips won't help us save the world. 

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