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

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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 ...
12
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6answers
13k 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 ...
12
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3answers
7k 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 ...
11
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1answer
274 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, ...
9
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3answers
2k 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 ...
8
votes
7answers
2k 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, ...
8
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2answers
2k 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 ...
7
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3answers
649 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? ...
7
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3answers
396 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 ...
6
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3answers
737 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 ...
6
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2answers
1k 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 ...
6
votes
1answer
979 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 - ...
5
votes
3answers
230 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
144 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
1k 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
260 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 ...
5
votes
3answers
3k 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 ...
5
votes
1answer
13k 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 ...
5
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1answer
458 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 ...
5
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1answer
1k 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
298 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 ...
4
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6answers
4k 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 ...
3
votes
5answers
2k 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: ...
3
votes
3answers
270 views

Why should every file have a user and a group?

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 ...
3
votes
2answers
122 views

How can I ensure that Dropbox is using only its folder?

I'm using several cloude storage services, like Dropbox. Each have windows app for its synchronization, and this app actually can read anything from my disc, not just files from its 'synchronized' ...
3
votes
3answers
573 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 ...
3
votes
2answers
270 views

Which access rights should be chosen for doku wiki?

I'm currently making my first experiences with a CMS called "DokuWiki" (Link). This CMS needs only PHP and writes the information to files (seems to be /dokuwiki/data/pages). At the moment I gave the ...
3
votes
2answers
290 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 ...
3
votes
2answers
846 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 ...
3
votes
2answers
72 views

What precaustions should be taken when the file displayed by a webpage is specified by the GET value

My website shows some files based on the get value in the URL. For example http://www.mysit.com/navigate.php?d=firstpage.html The thing is navigate.php knows which folder to look in and it's not in ...
3
votes
1answer
658 views

Recognizing PGP-encrypted disks

I am studying various disk encryption schemes (such as PGP, MS Bit Locker, BestCrypt and TrueCrypt) on my Windows OS. I am interested to know how an encrypted partition/disk/file with a particular ...
3
votes
2answers
894 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 ...
3
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5answers
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Security purpose of asking admin password to mount partition on Linux

So I divided my 250GB laptop drive into 2 partitions and some swap. On the second partition which is an ext4 60GB partition I installed Fedora 17. On the other bigger NTFS partition I've got Win XP ...
3
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2answers
2k 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 ...
3
votes
3answers
2k 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 ...
3
votes
1answer
987 views

Which Domain Administrator created file X on a Windows 2008 R2-based server?

Someone created a file (web.config) in a location that basically caused IIS to not work. Is there any way I can determine who created this file? The creator/owner says "Domain Administrators". ...
3
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2answers
2k 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 ...
2
votes
5answers
532 views

How to restrict flash drives in Local Area Network

It is prohibited to use USB drives at our office, due to security reasons. But some people still use them to steal information. It is now a great risk factor at our office. Now we need to ensure any ...
2
votes
5answers
1k views

Prove that you deleted the file

Is it possible to prove a date that you Deleted a file through the recycle bin? I delete a folder of pictures 2 months ago and somebody is asking to prove that I did it.
2
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3answers
198 views

Theft of data via live boot disk

I have been working with live boot disks recently and I know that it gives you access to the computer's processing power, internet, and various other tasks without the hassle of a username/password. ...
2
votes
3answers
248 views

How to protect data on your hard disk if it is in an unfriendly environment?

The essence of the problem as follows: There is a server located on the side of our company. There is a hardware client module, which is in a public place, which communicates with the server via a ...
2
votes
2answers
91 views

How risky is having sensitive files on webroot?

I understand that having anything sensitive under webroot is not smart; someone may be able to access it via url. However, I do not have a choice with my web host (iPage) as they limit my server space ...
2
votes
1answer
62 views

Where to store uploaded images from perspective of security

It is quite common that uploaded files (images, videos, etc.) are stored on a file server because of performance and database-recovery-time reasons. But is there a benefit of storing such files in ...
2
votes
1answer
63 views

Are files created in Chrome OS developer mode tracked by Google?

If I enable developer mode, then open a shell and create /some/directory/temp.txt, it is invisible to me through the Chrome Filesystem API. But does this mean that it's also invisible to Chrome OS ...
2
votes
3answers
135 views

Wipe free space or take image and wipe entire disk?

Read some of the stuff here regarding wiping disks and securely deleting files. From what I've understood, after deleting (not securely) files they become part of the unallocated(free) space of the ...
2
votes
1answer
1k views

Is the mount manpage saying nosuid *is* secure, or is *not*?

I'm a bit confused about the description of nosuid in the mount manpage on this RedHat system I'm setting up: nosuid Do not allow set-user-identifier or set-group-identifier bits to take ...
2
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1answer
934 views

Extract SquashFS filesystem with shsq magic number [closed]

for a few days I was trying to extract the filesystem of a router firmware. Checking the image that the vendor provides I can see a SquashFS flag on it: DECIMAL HEX DESCRIPTION ...
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4answers
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Writing file shredder

I want to write a simple file shredder in c++, i.e. a program that deletes a file so that it is not recoverable. Would the following be a secure and correct way to do that? (1) Open the file with ...
1
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3answers
154 views

How to minimise risk to sensitive data in temp files in shared hosting environment before encryption?

openssl_pkcs7_encrypt() requires the data to be encrypted to be read from a file and so unfortunately it requires sensitive data to be written to temporary file before being encrypted. In a shared ...
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2answers
403 views

best practice for encrypted filesystem inside a file

This is an extension of my question on UNIX. Let's suppose I create a file, map it to /dev/loop0, and create a LUKS partition inside dd if=/dev/zero of=myfile bs=1M count=1000 losetup /dev/loop0 ...