238
votes
Accepted
Why is the OS obfuscation defense against "It's a Unix system!" not widely implemented?
Before I tear your idea apart, let me say that it's a really interesting idea and it was super fun to think about.
Please continue to think outside the box and ask interesting questions!
Alright, let'...
- 59.3k
154
votes
Can you hide your OS from programs? Can you trick a program into thinking you are on a different OS?
Cheeky answer: I think you are about to invent a Virtual Machine.
In order to spoof the hardware to look like a 2003 motherboard you'll need to deal with things like writing a CPU instruction ...
- 59.3k
123
votes
Accepted
Can a virus destroy the BIOS of a modern computer?
Modern computers don't have a BIOS, they have a UEFI. Updating the UEFI firmware from the running operating system is a standard procedure, so any malware which manages to get executed on the ...
- 49.5k
91
votes
Why is the OS obfuscation defense against "It's a Unix system!" not widely implemented?
Mike's answer says basically everything I have to offer about why this is a bad idea from a development perspective (and, as Ghedipunk's comment says, an unusable security feature provides no security)...
- 52.1k
79
votes
Accepted
Is an up-to-date browser secure on an out-of-date OS?
Do not use an outdated OS, even with a modern browser.
Assuming that after that day I still use an updated browser, is it true that I'm still safe?
No, you cannot avoid browser-based security ...
- 67.3k
66
votes
Accepted
Can you create a fake (malicious) Ubuntu iso
If an OS is open source or not is not the important factor if someone could build a malicious installer image.
Recent versions of Windows use a technique that bases on WIM images which can be ...
- 1,471
61
votes
Accepted
Why is there a need to modify system call tables in Linux?
You can check if they are read-only by looking up the kernel symbols. The "R" means read-only.*
$ grep sys_call_table /proc/kallsyms
0000000000000000 R sys_call_table
0000000000000000 R ...
- 67.3k
56
votes
Would it be more secure or not if all computers in the network use the same operating system?
In 2003, Dan Geer from @Stake published a seminal paper on this very topic - CyberInsecurity: The Cost of Monopoly. Surprisingly (given that he was employed by Microsoft at the time) he comes ...
- 73.3k
48
votes
Accepted
Are there any OSes that verify program signatures before executing them?
iOS and Android both validates the signature of every single piece of code before loading them into memory.
Windows UWP apps are also all checked for signature before being loaded as well.
Package ...
- 18.7k
48
votes
Can a virus destroy the BIOS of a modern computer?
Yes, it is definitely possible.
Nowadays, with UEFI becoming widespread, it is even more of a concern: UEFI has a much larger attack surface than traditional BIOS and a (potential) flaw in UEFI ...
- 18.7k
46
votes
Accepted
What are the risks of desktop personalization on Windows?
Changing them to other Windows defaults would pose no security risk.
Allowing people to install fonts or screensavers from third parties poses a HUGE security risk.
However, it's most likely these ...
- 8,275
39
votes
Why might an operating system require a restart after N failed login attempts?
I can think of a few different benefits:
It slows down the attack, as you have to wait for the reboot to complete.
A reboot may be more noticeable (either to a monitoring system or other physically ...
- 16.5k
32
votes
Would it be more secure or not if all computers in the network use the same operating system?
If all the systems are the same, then there is predictability of what could go wrong and how to fix and patch. It becomes a lot easier to mitigate problems that you know about. For instance, if the ...
- 132k
31
votes
Can you create a fake (malicious) Ubuntu iso
First of all:
This would require a faked checksum as well, but that is somewhat besides the point because it can be faked too.
What do you mean by faked? If the user checks the checksum against the ...
- 583
30
votes
Why is the OS obfuscation defense against "It's a Unix system!" not widely implemented?
If your objective is to deprive an attacker of ls and cat, there's an even better alternative to obfuscation: just don't install those utilities.
While I wouldn't say this is a widely implement ...
- 725
30
votes
What is the frequency of open security bugs in an operating system with increasing age?
Interesting theory but...
Even in open-source code, serious bugs can go unnoticed for a very long time (think Log4j), because nobody had the time or inclination to analyze the code. Probably, a three-...
- 8,465
28
votes
Are there any OSes that verify program signatures before executing them?
Why do not all OS verify signature of programs? Simply because in the early times, most programs were written and compiled locally, and still nowadays, some business applications are specifically ...
- 26.9k
27
votes
Accepted
Should I worry about compromised firmware when reinstalling an OS?
Basically yes, you're right to worry. However, it's not the garden variety adversary that has that kind of capabilities... Also more and more update mechanisms are protected by a signature check, and —...
- 5,507
26
votes
Accepted
How do I hide the OS I am using from internet sites?
It is not currently possible to hide the type of OS from a website
A solution against general fingerprinting and obtaining more specific information about your system is to use Tor Browser with the ...
- 436
25
votes
Can you hide your OS from programs? Can you trick a program into thinking you are on a different OS?
Depending on the level of "trick" you want, you might be able to do this with built-in compatibility features. Windows supports running programs in special modes that emulate older versions and/or ...
- 52.1k
23
votes
Why is there a need to modify system call tables in Linux?
As noted by forest, modern Linux does not allow this, but it's easy to override.
However, historically it was useful (and maybe still is) for security purposes: hot-patching against vulnerabilities. ...
22
votes
What are the risks of desktop personalization on Windows?
Sometimes blocking desktop personalisation can be a HR issue rather than a security one. For example, if you allow people to set their own backgrounds, sooner or later someone is going to set ...
- 16.5k
21
votes
Accepted
What are the criteria to choose a secure operating system?
There are many criteria you can use for choosing a secure operating system. This includes everything from the features explicitly supported to the overall goal of the system itself. Although this ...
- 67.3k
21
votes
Can a virus destroy the BIOS of a modern computer?
Practically speaking, a virus is software, so can do anything that any other software can do.
So the simple way answer to this question, and all others of the class "Can viruses do X?" is to ask "...
- 1,439
19
votes
How can Linux be secure if it allows for open source contributions from the public?
You are misunderstanding how open source software development works. Not just anyone can modify the kernel, so no "unknown developers from around the world" are submitting mysterious lines ...
- 67.3k
15
votes
Why might an operating system require a restart after N failed login attempts?
To elaborate on Gh0stFish’s answer, I think that the far most likely reason for a restart is to kill any running processes.
While a restart would kill all, it’s presumably intended to kill sensitive ...
- 3,025
13
votes
Is penetration testing becoming objectively "harder" as apps/protocols/operating systems become more secure?
The objective of penetration testing is not to find vulnerabilities, and so it hasn't failed if it doesn't find any. It's to check whether or not vulnerabilities are present. It doesn't get harder if ...
- 10.3k
13
votes
Would it be more secure or not if all computers in the network use the same operating system?
More diverse systems make it more difficult for an infection to spread.*
Less diverse systems make it more difficult for an infection to start.**
So if your failure scenario is all your systems ...
- 3,630
13
votes
Can a virus destroy the BIOS of a modern computer?
Yes, it is definitely possible.
Here is an example of a malware OS update fraudulently signed with the manufacturer's private key:
https://www.theregister.co.uk/2019/03/25/...
- 231
13
votes
Is an up-to-date browser secure on an out-of-date OS?
One benefit of the newer operating systems, like Windows 10 over Windows 7, is that they have more advanced features built in to the operating system to protect against entire classes of ...
- 131
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