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52

We always hear... Do we? I don't. Installing some untrusted program as a normal user is a bad idea with Linux the same it is with Windows or Mac: this program has access to all your data and can delete these data, send these data to somebody else etc. Moreover it can make screenshots, control other applications running on the same X windows screen ...


30

In short: yes, being on a low-privilege account helps protect you against malware, but does not make you immune. Like any security measure, no single thing is going to keep you 100% safe. TL;DR: Running on a low-privilege account (aka "principle of least privilege") should be part of a balanced breakfast which also includes good firewall configurations; ...


23

I was curious of this myself once, and wrote a small program under linux that malloc'ed all available memory and dumped it to disk. It turned out that it was all zeroed out before it was handed to my application. Later, I also checked the kernel code, and could confirm it was the kernel who did it. -- I think it makes perfectly sense that it is the OS ...


17

Yes, it can be done as (theoretically) every "computing device" is computationally equivalent to every other computing device. Look up the Church-Turing thesis if you are interested. However your question is grounded in practice and in this case the answer is "yes, but it would cost too much". Effort in virtualisation today aims at speeding up the virtual ...


17

In Linux, processes is able to read another process memory when any of the following conditions applies: The process had root permission or it can read /proc/$PID/mem or /dev/mem, by default /proc/$PID/mem and /dev/mem are only accessible by root Parent process can fork()/clone() in such a way that allows it to read some or all memory of its child ...


12

A "sandbox" is a play area for young children: it is supposed to be safe for them (they cannot hurt themselves) and safe from them (it is sand, they cannot break it). In the context of IT security, "sandboxing" means isolating some piece of software in such a way that whatever it does, it will not spread havoc elsewhere. A common Unix way of sandboxing is ...


12

It seems to me you're discussing two things: sandboxing on the desktop and then strategies for user content access in sandboxed applications. Sandboxing There are many sandboxing models out there, including the ones used by OSes: Windows 8 WinRT Store Apps OS X Sandboxed Store Apps iOS Apps Android Apps Some apps are shipped sandboxed, for instance ...


11

Codepad explains how they provide security on their about page: codepad.org is an online compiler/interpreter. [...] The strategy is to run everything under ptrace, with many system calls disallowed or ignored. Compilers and final executables are both executed in a chroot jail, with strict resource limits. [...] Rather than rely on just the chroot ...


10

Chroot wouldn't give you any security anyway, it's only designed for very specific use cases. See Debian unstable chroot security issues and chroot "jail" - what is it and how do I use it?. Any application that has access to the X server can do a lot of things. It can snoop on other applications that display windows on the same server. It can log key ...


10

Each version of Android is incrementally stronger on this front than the previous, and Lolipop certainly pushes application sandboxing a step further than Kitkat, particularly with respect to inter-app isolation. Third-party "firewall" apps on Android are probably a bit over-hyped, and the level of protection they can offer without rooting is in my opinion ...


8

According to the diagram on the NACL site, the NACL code runs with the same privileges as the renderer which is a reduced privilege process. If NACL fails, an attacker can take over the renderer, giving them access to resources in the same renderer process (set of frames that could be in the same domain after some set of document.domain sets). "The ...


8

On Linux, you can reliably monitor a selection of system calls or file accesses with the audit subsystem. Make sure the auditd daemon is running, then configure what you want to log with auditctl. Each logged operation is recorded in /var/log/audit/audit.log (on typical configurations). You'll find simple examples of auditctl usage on this site, on Server ...


8

The attack you describe doesn't work on Windows. Starving the page-zeroing thread doesn't prevent zeroing, it only delays it. The existence of the page-zeroing background task is a performance optimization. Basically, a naive memory manager with a privacy guarantee works like this: reserve a page from the freed list zero it make it available to ...


7

Why aren't applications sandboxed by default on Windows? I don't know, but I'm guessing it is a mixture of the following reasons: Sandboxing breaks many applications, in complex and subtle ways. Users will be unhappy if Windows turns on a new feature by default that breaks even one of their applications. It is very, very difficult to design an ...


7

The most secure approach is to run the proprietary software in a virtual machine (VM). This is pretty simple to set up, and you can find free VMs (e.g., VirtualBox). However, since you mention games, this may not work for games (it may produce unacceptable performance degradation in some graphics-intensive games). Another possibility is to install a ...


7

The term "sandbox" is wide, generic, and often misused and misunderstood. Let's consider a type of sandbox, a virtual machine running under control of an hypervisor. The guest system is nominally isolated and cannot "see" the host system. However, this is relative to the implementation of the hypervisor, which is a combination of software and hardware, both ...


7

Honestly some people need a wake up call before they take responsibility for their mistakes. Give the company a set time, like one month from today to release a patch. If they do not comply post information about the vulnerability on the Full Disclosure Mailinglist. By not making this information public then you are risking that organized crime will ...


7

Actually lorenzo's answer does not quite cut it. The Church-Turing thesis only provides us with a model of computing, it can't tell us anything about virtualization because it is not concerned with other aspects of a machine. But there is theoretical analysis for the ability of a machine to be virtualized by Popek et al: ...


7

This is a horrible case of Security Theater Security Theater is the practice or belief of something that looks like it improves security, but in reality does little/harm to it. This false belief has been around as long as the following rumor Linux has no viruses because of it's permission system That's almost as good as saying I don't have a ...


6

I'm far from being a PHP expert, so my comments are more general rather than specific. Probably not entirely, but it depends. I don't think that any whitelist/blacklist approach can ever be 100% accurate. There will always be a case of false positives or false negatives. So you're always balancing between hits (of a script being able to still penetrate ...


6

There are two approaches, the quantitative and the qualitative. The quantitative consists of fuzzing the input to the sandboxing driver. Use a fuzzing framework like Peach, Sulley or other to fuzz that input and look for crashes or file operations outside the sandbox. The qualitative approach involves reverse engineering and understand the sandboxing ...


6

See this question for a sense on how secure VMs really are. How secure are virtual machines really? False sense of security? A good general rule is to not allow the VMs to communicate with each other through networking. This means proper measure to segregate network access should be enforced. If you notice a compromise on any of the VMs, immediately nuke ...


6

A sandbox is like a special "section" of your computer that has been blocked off from accessing the rest of your computer. In a perfect sandbox you can do anything you want within it, but it will not effect the rest of your computer. This is used as a form of security, keeping any malware you might download from being able to affect the rest of your ...


6

Hard to answer because we can have a lot of horizons here. Short answer: I will use your bank as an example. Let's say you open a new tab and enter on your-bank.com. If your bank has not explicitly developed any code to communicate with other tabs, no other tab could say that you are browsing your bank and what you are doing there.* EXCEPT if a ...


6

tl;dr: container solutions do not and never will do guarantee to provide complete isolation, use virtualization instead if you require this. Bottom up and top down approaches Docker (and the same applies to similar container soluations) does not guarantee complete isolation and may not be confused with virtualization. Isolation of containers is achieved ...



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