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Questions tagged [file-system]

A file system is a way of organizing information on a storage device like a computer hard drive.

126
votes
9answers
34k views

What stops Google from saving all the information on my computer through Google Chrome?

I noticed that in Google Chrome, if I type in file:///C:/Users/MyUsername/Desktop/ it shows me all of the folders on my Desktop, and I can type open up PDFs and such in chrome just by typing in the ...
58
votes
6answers
25k views

Unix execute permission can be easily bypassed. Is it superfluous, or what's the intention behind it?

The unix read permission is actually the same as the execute permission, so if e.g. one process has write access it's also able to execute the same file. This can be done pretty easily:First this ...
28
votes
6answers
31k views

How secure is NTFS encryption?

How secure is the data in a encrypted NTFS folder on Windows (XP, 7)? (The encryption option under file|folder -> properties -> advanced -> encrypt.) If the user uses a decent password, can this ...
21
votes
1answer
2k views

I forgot to shred a file before deleting it (on Windows). How do I shred that part of file system now where the file was located?

My company has a policy that files have to be shredded after they've been read. They provide with a tool shred.exe that I run on the file and it overwrites it with garbage in the file system before ...
16
votes
2answers
2k views

Could you write custom data to a file of a specific extension and use it to hack a program once it opens the file?

From what I understand file extensions don't really affect the data contained within them at all. They just give your computer a hint of what the data is, how it's structured and your computer then ...
13
votes
3answers
4k views

How to recover securely deleted data

Since we all know files are recoverable with programs after being deleted from the recycling bin, everyone is told to do secure wipes by putting random data over the files you're deleting on the disk ...
12
votes
4answers
3k views

Why is it impossible to verify whether a file has been modified since creation?

From what I understand, it is impossible to verify whether a file has been modified since its creation. Specifically, I was wondering whether it was possible to verify whether a photo was modified ...
12
votes
3answers
10k views

Prevent acccess to the C drive on Windows systems

Is it possible to prevent regular users from accessing the C drive via Windows Explorer? they should be allowed to execute certain programs. This is to ensure that employees cannot steal or copy out ...
12
votes
1answer
368 views

A filesystem with chunks hidden all over the internet?

I am wondering if there are any implementations of a filesystem (as in FUSE) that would allow me to host a file in chunks steganographically distributed all over the internet. The way I imagine it, ...
11
votes
9answers
4k views

Is there any asymmetrically encrypted file system?

Is there a file system providing a directory where everybody can write, but only the directory owner can read the files? In theory it could be done by encrypting using the public key while writing, ...
9
votes
3answers
1k views

What prevents this exploit from working (unix SUID)?

If I have a user on a unix system where Im allowed to create new files, what prevents me from downloading an executable file onto that system which is already SUID'ed to root on a different system? ...
9
votes
2answers
4k views

Best way for a hacker to hide a file on Linux?

Suppose a hacker obtains a shell on my Linux host and wants to hide a file. What's the best way for him to do this? You may assume unprivileged or root access. My thoughts are Use a .file filename ...
9
votes
2answers
4k views

What are the dangers of storing webserver temp files in the /tmp/ folder?

I have configured my first publicly accessible nginx server. I have configured it to use a /tmp/nginx folder to store temp files. This includes the body of http requests, proxy files etc. The /tmp ...
9
votes
3answers
210 views

Finding artifacts of software

I was wondering if there is an established way to know what a running particular program on a system might leave behind (in terms of changes to a filesystem, such as in Linux). I am thinking of this ...
8
votes
9answers
13k views

Is there a file system that doesn't support encryption?

I would prefer that no one, even me, could encrypt my files. I have no use for it, and don't want it. Is there a way to permanently disable any sort of encryption at the OS level? If not, is this a ...
8
votes
3answers
588 views

Secure cleaning of deleted files

So I know how to secure delete files. But at our company, we have a laptop which had many important documents, which now have been deleted, but not in a secure way. We can't perform a full format of ...
8
votes
2answers
654 views

Are there any filesystems that have secure deletion as a feature?

There's many 3rd party tools people have designed to perform secure deletion, but I don't know of any filesystems where secure deletion is built in. In fact, secure deletion has to work around ...
8
votes
3answers
5k views

Can someone tell if you delete deleted files?

I am aware that to delete something completely we will have to use a program that over-writes the deleted file such that it is unrecoverable. Is there anyway to tell that this has happened? Or is the ...
8
votes
1answer
2k views

Database encryption or filesystem encryption?

Recently I've been working on some data which, although not directly governed by any infosec laws, is sensitive enough to warrant being encrypted. I'm interested in finding out about best practises ...
8
votes
1answer
199 views

Anonymity of sneakernet: identifiable information on removable storage

Alice, an anonymous informant, would like to transmit digital documents to Bob while maintaining her anonymity. For whatever reason, she chooses to copy the documents to some kind of physical ...
7
votes
3answers
1k views

How effective is something like Deep Freeze against boot sector infections?

I work for an embedded system manufacturer and on our older generation systems, which are powered by Windows Embedded, a number of customers have been experiencing virus infections. Due to the real ...
7
votes
2answers
15k views

How can I identify / discover files hidden with ADS?

ADS, or alternate data streams, were added in to Windows in 1993 (First Windows NT version) as a feature of the new NTFS file system to help support some features of the Mac OS at the time. I like to ...
7
votes
4answers
658 views

Special form of file system to prevent recovering after secure wipe data

I'm looking for file system with reasonably error corrections, but rugged against forensic after wipe. Say, encrypted container via loop mounted like ext4 - journal file system. This is good ...
7
votes
2answers
11k views

How can I view the NTFS $MFT using correct field names?

I am trying to view an NTFS master file table. Each tool I have used so far extracts all of the entries, but puts non standard headers such as STANDARD_INFORMATION_ON instead of say $...
7
votes
1answer
2k views

Hadoop security, isolation, and hardening

This is a multiple part question, which all really come back to the main question: How best to protect data in a Hadoop (wikipedia) cluster. (Current version, vanilla main-branch distro - ...
6
votes
8answers
13k views

Overwriting hard drive to securely delete a file?

I am working on a computer that I am not allowed to install new software on. It does not have secure delete software installed. Suppose I have a file (or files) that are sensitive that I'd like to ...
6
votes
4answers
1k views

What's a good secure file deleter

I've used cipher \w which is built into Windows to overwrite free space but I'm looking for a tool that securely deletes files which have not been deleted yet. It would be a plus (but certainly not ...
6
votes
1answer
23k views

Repairing corrupt TrueCrypt volumes/disks?

(I'm asking this for a friend of mine as I'm trying to help him with this problem over remote desktop, so if any details are needed, just ask and I will get them). Two entire hard disks were encrypted ...
6
votes
2answers
473 views

`rsync -K`-based exploit

In the description of the -K (--keep-dirlinks) flag, the rsync man page gives this warning (my emphasis): One note of caution: if you use --keep-dirlinks, you must trust all the symlinks in the ...
6
votes
3answers
200 views

Live OS : secure file deletion

In the case of a Live OS (i.e Tails) where filesystems are kept in RAM, is there any difference in the way a file is deleted ? Specific case considered : files "1.jpg" and "2.jpg" in a running Live ...
6
votes
2answers
358 views

Path Disclosure without ability to read files

So I am a pentester, and I have discovered "feature" on a server that allows me to, essentially, blindly traverse a web server's files (without executing or reading them). The problem is that I ...
6
votes
1answer
514 views

Run native code from shell on read-only filesystem

I'm researching an embedded device running Linux, busybox, and a few custom services. I've found a way to obtain unprivileged shell access, and trying to see if it's possible to escalate privileges. ...
6
votes
1answer
393 views

Are NTFS Alternate File Streams considered a security risk in your organisation; how is it mitigated?

Alternate File Streams allows a user to embed hidden content within any NTFS file. That file can be a TXT file, or MOV for example. Some may consider this a form of steganography, and therefore the ...
5
votes
3answers
289 views

Could browsers improve security of stored passwords by using setuid?

On Unix-esque systems, Mozilla Firefox stores a users' preferences, web history and stored passwords in a set of files that are readible and writeable by that particular user. This makes sense: when ...
5
votes
2answers
3k views

Raw hard disk data extraction possible?

Suppose that the administrator's account is hacked. Then, can a hacker extract hard disk raw data (by raw data, I mean every raw data, not just files that can be read by a file system.)?
5
votes
2answers
223 views

Monitoring a specific application for creation or modification of files

I don't know if I'm looking for a file integrity monitoring software here. Basically let's say we have firefox or chromium, let's say the user is watching a youtube video, then we'll find that video ...
5
votes
2answers
2k views

Is it possible to browse/access the files on a computer's hard drive by booting from an OS installed in a flash drive?

I have installed Tails in an USB flashdrive and then booted my macbook with it. I noticed that Tails was capable of seeing my macbook's hard drive. Out of curiosity I tried to browse it. ...
5
votes
2answers
2k views

Possible implementations of networked+encrypted filesystem

Is it possible to implement scheme where remote server just share its filesystem (or resizable container file in it) and it's locally encrypted and mounted? And what is best practical method? (On ...
5
votes
3answers
3k views

How to check for null byte injection in Java webapp

Looks like Null Byte Injection is possible in Java apps. see: Is null-byte injection possible in Java filenames? So how does one protect against it? Inspect all the bytes of the filename for a 0 (...
5
votes
1answer
77 views

Is there a file system allowing read-only access enforced by cryptography

Is there a file system standard (like LUKS) that allows anyone who can plug in the hard drive to read files, but requires a passphrase to modify or write? For example, I can do something similar by ...
5
votes
1answer
3k views

Windows mandatory access control: How to remove “mandatory level” label from the file?

1) How to remove "mandatory level" label from the file? I have two files, for first icalcs return Mandatory Label\Medium Mandatory Level:(NW) for second icalcs doesn't return anything (that means ...
5
votes
1answer
192 views

Web application reacts differently to Windows reserved names like CON, AUX, NUL

Several web applications I tested have the behavior that reserved Windows filenames such as AUX, CON, NUL, PRN, COM1, LPT1 have different behavior than other pages. For example, http://example.com/foo ...
4
votes
3answers
6k views

Are file permissions set in Unix/Linux effective in Windows or Any other OS?

Consider some files and folder in Unix/Linux OS which are configured for only read access by root, if the hard drive stolen, and used in Windows Environment, are these permissions are still effective? ...
4
votes
5answers
7k views

How do I run an unknown .exe file without being in risk [duplicate]

I would like to know whether there is any way I can run an absolutely unknown executable file without being hacked even if the file contains a lot of malicious code. Is there any program in which I ...
4
votes
3answers
1k views

How do polymorphic/metamorphic/self-encrypting/self-changing file infectors know if they have infected a file or not?

If a virus rewrites itself for each infection how would it know if it has infected a file or not? If it keeps infecting the same file soon the whole file structure will be corrupt. For example how ...
4
votes
5answers
5k views

Is running an erase tool after an OS install sufficient to ensure no data from the old install is recoverable?

How secure do you consider this process? A drive has data from a previous OS installation. A new OS installation is made on the drive, and Heidi Eraser is run on free space. What are the chances of ...
4
votes
1answer
3k views

External hard drives: 'date last accessed' file?

I'm trying to figure out if there's a way to figure out when files on my external hard drive were last opened. I'm using a Seagate Backup Plus, and it's both mac and PC compatible. BUT, I've also read ...
4
votes
2answers
727 views

Possible to detect an/or shut off CryptoLocker by limiting total network bytes transferred?

Since a virus infected PC has to download (encrypt) reupload the entire file (to a file server), and repeat the process for every network drive, is is possible to detect this unusually high bandwidth ...
3
votes
5answers
4k views

Secure mount options + partitioning on Ubuntu

What is the best solution for mount options/partitioning when having e.g.: an Ubuntu minimal install (11.04) for Desktop use? e.g.: put /tmp on different partition to give it mount options like: nodev,...
3
votes
3answers
559 views

Why should the user ID and group ID of every file match an existing user?

I've been reading in most hardening guides for Linux, that you should check for files and directories without valid user or valid group. What I can't find, is how this could be used for an attack, or ...