Securing Linux systems and applications; understanding Linux security features.

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2answers
437 views

Directory traversal & default filesystem permissions (755) for web server

I'm trying to get a better understanding of the potential security holes my default filesystem permissions might be creating. It appears I am capable of traversing my filesystem, serving simple php ...
5
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2answers
823 views

Escalating from Apache shell to root

I have one noob question.I tried to exploit shellshock on my Slackware linux server, but after I connect with reverse shell and User Agent I get that I am apache user and apache user don't have too ...
4
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2answers
243 views

How secure is BSD sockets?

BSD sockets API was released in 1983. As it was implemented 3 decades ago and still being widely used, is it secure in today's scenario where every software has to be actively protected against ...
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2answers
254 views

“Shell shock” - exploitable when `system()` syscall or `exec(bash)`, right?

Is my understanding correct that in order to exploit via "Shell Shock", binary we influence needs to execute bash (and we need to have influence on command line)? Therefore, am I correct, that if ...
1
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1answer
142 views

Can shellshock be used on a system with public webpages but restricted server access?

I want to know if my servers are still vulnerable under the following conditions... My servers are private - only myself and trusted developers have access to them We have enabled executables within ...
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1answer
288 views

Has CVE-2014-6271 Shell Shock been mitigated completely what is the latest? [closed]

I have patched my system however CVE-2014-7169 claims that the fix for 6271 was incomplete. Sure enough if I run the command below: env X='() { (a)=>\' sh -c "echo date"; cat echo It appears ...
8
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1answer
619 views

What does this attempted Shellshock exploit do, and has my website been compromised?

I grepped my Apache's access.log today for the now infamous () { string, and besides a bunch of what seemed like pings to check how many servers are vulnerable, I found this attempt, which looked like ...
8
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2answers
2k views

Is connecting to an open WiFi router with DHCP in Linux susceptible to Shellshock?

Source: http://lcamtuf.blogspot.com/2014/09/quick-notes-about-bash-bug-its-impact.html For the same reason, userland DHCP clients that invoke configuration scripts and use variables to pass down ...
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2answers
179 views

what makes envirnments vulnerable/protected vs shellshock bug

I just tested whether or not my university's environment was vulnerable to the shellshock bug using env X="() { :;} ; echo busted" /bin/sh -c "echo stuff" (code from ...
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1answer
74 views

Am I safe to see a thumbnail of a downloaded images on Ubuntu 14.04?

I have downloaded an image that someone has uploaded to my website with a public upload form. My intention was to copy the file in a virtual machine and see the image from there; unfortunately, on ...
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0answers
99 views

Tunneling Remote Desktop from DMZ Windows server to my Listening Linux Server. How to?

I have a situation in a penetration test where I got a meterpreter on an internal (DMZ) Windows box, and I want to connect via RDP to it, however the RDP port is blocked externally. The box I hacked ...
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2answers
869 views

How to completely password protect login into Ubuntu 12.10?

I am running Ubuntu 12.10 on my laptop and I would like to make a set up such that without a login password, no one would be able to login into my system. Currently it seems that one can, quite ...
1
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1answer
92 views

Is this a secure way to connect with Tor?

I was discussing the use of tor with a friend, and he happened to suggest a way to remain secure when using applications on the terminal (Lynx, Nmap etc.) His suggestion was this: ssh-keygen -b 4096 ...
2
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2answers
129 views

Receiving sensitive data uploaded on a Web server, and remotely accessing it without exposing it to theft

Edit: I mostly used my university's guidelines on how to meet DPA standards and their own. I extrapolated a bit because encryption on a VM hosted by my uni that is already probably encrypted makes ...
14
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2answers
2k views

Linux password changed. Is this an attack or a hardware glitch?

My Linux (Ubuntu 12.04) password suddenly changed last night and I'm not sure if this is an attack or just a hardware/user error. This is on a personal/non-server box. Several strange events led up to ...
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3answers
118 views

Not replacing SSL cert on a rebuilt, formerly rooted Unix Server

If a server was rooted, to the point that we know a Perl script which creates a remote shell was placed on the filesystem remotely, and the server was rebuilt entirely, patching the original Apache ...
4
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1answer
6k views

Fail2Ban does not ban failed root login attempt

I have a small server which only open ports are ssh, http and https. I have fail2ban installed and set up so that after 3 failed attempts someone gets blocked for 10 minutes (thats the dafault I ...
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5answers
897 views

What voip client support manual encryption?

In pidgin there is a plugin that we can use to encrypt our messages in chat windows .. Is there anything simular for voip (pc to pc) ? any client that support manual encryption for voice data?(linux)
2
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1answer
175 views

Linux Rootkit / BIOS Malware: What packages are necessary to get infected?

Everybody knows about the dangers of Rootkits / BIOS malware. What do you say about this countermeasure? In order to actually get infected the malware needs to use the OS to 'patch' the BIOS chip. ...
0
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1answer
119 views

Wireshark: could “Follow TCP Stream” yield an empty window? or is it a bug?

I am capturing a pop3 netcat connection (port 110) using Wireshark, on Debian linux (Kali). After filtering packets with (tcp.port eq 110) I get few packets but once I R.Click on any and click "Follow ...
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1answer
124 views

Fuzzing shared libraries

Are there any tools capable of automatically fuzzing Linux shared libraries, by automatically I mean detect exported function, determine function signature and finally inject random data ? Can ...
3
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3answers
119 views

How do I ensure that my Ubuntu download has not been tampered with?

I am downloading Ubuntu Linux, and would like to make sure that my download has not been tampered with. Ubuntu has a GPG key, which I could use to make sure that the download is valid -- but how do I ...
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3answers
5k views

Retrieve auto saved Skype password from Ubuntu 12.04 LTS

The email address I used to create Skype profile has been disabled and I can't get it back. Unfortunately, I don't remember the Skype password now. As the password is auto saved in my local machine I ...
1
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1answer
164 views

What are the options for acquiring disk image from a Linux computer that can't be removed from a crime scene?

If the suspect's computer is Linux, can you directly use tools such as dd or dcfldd on his computer to acquire the disk image? Or do you need to use forensic live cds like Helix, Penguin sleuth or ...
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2answers
193 views

Where can I “hide” easter eggs for students learning about Linux security?

I feel like this isn't the best place to ask this (since there's no single right answer), but I can't think of a better place. If you have a better recommendation, could you please recommend it and I ...
39
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6answers
6k 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 ...
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1answer
226 views

SElinux security context public_content_t for vsftpd

My understanding of SElinux context public_content_t is as public_content_t is required for files shared via a FTP server unless associated with a user home directory Here is my question Does user ...
2
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2answers
897 views

I ran a netstat on my server and port 80 is listening, does that mean it is open and vulnerable to attacks? [closed]

Sorry I am just getting into Web Development and trying to learn more about servers and PHP, so I downloaded the LAMP stack on an Ubuntu14 OS and started an apache2 server. tcp6 0 0 :::80 ...
4
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2answers
1k views

How to pass PCI DSS 2.0 anti-virus requirement (5.1) on Linux?

PCI DSS 2.0 Requirement 5.1 states: 5.1 Deploy anti-virus software on all systems commonly affected by malicious software (particularly personal computers and servers). This requirement ...
2
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2answers
716 views

Using a TPM with Linux

I have the need for a company laptop (Dell e6540) that contains our java application on it to go out for evaluation purposes. For this reason I would like to make sure that the HDD is protected from ...
1
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1answer
48 views

updatedb and encrypted home folders: Does it store unencrypted file and folder names somewhere?

When you encrypt your home folder in Ubuntu and Debian, it protects not only the file contents but also the file and folder names. Yet I see that updatedb and locate works in Debian. When I run ...
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1answer
59 views

How do I secure X server against spyware in a GUI application?

Suppose you have a GUI application, that potentionally may be too curious about your environment, such as the list of window titles. How do I limit application's ability to enumerate windows, capture ...
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3answers
22k views

Simple example auditd configuration?

Auditd was recommended in an answer to Linux command logging? The default install on Ubuntu seems to barely log anything. There are several examples that come with it (capp.rules, nispom.rules, ...
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1answer
307 views

RHEL 6: PHP 5.3.3 - Is it inherently insecure?

I am talking about the PHP 5.3.3 package that is available in the Red Hat Enterprise Linux repository, running on Apache. From what I can see, as of RHEL 6, it is the latest version (no updates ...
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1answer
120 views

Which hardening methods are used in large linux desktops environments (i.e. Goobuntu)? [closed]

Im courious to know about how these large enterprises secure their linux desktop as Google does with ubuntu LTS. I am the only user at home with linux on the desktop and had already created some ...
0
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1answer
74 views

Limiting account access based upon NIC used to connect on Linux

I have a server which has multiple NICs (ignoring redundant pairs): 'inward' facing production (connects to other servers); 'outward' external facing production (connects out to the internet via a ...
1
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1answer
72 views

Linux file information leakage

What information is kept in a linux file about the user and/or system that created it? I want to make some files publicly available, posted on another server such as GitHub or FTP, but I'd rather the ...
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2answers
162 views

Why was LibreSSL PRNG unsafe on Linux?

From the source: https://www.agwa.name/blog/post/libressls_prng_is_unsafe_on_linux The first version of LibreSSL portable, 2.0.0, was released a few days ago (followed soon after by 2.0.1). Despite ...
3
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2answers
949 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 ...
4
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2answers
701 views

What Ubuntu packages are still affected by gnutls bug CVE-2014-0092?

Right now the internet is abuzz with news about a severe breach in GnuTLS. An update to the relevant GnuTLS packages has already been released. But I am worried whether some packages might have had ...
3
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1answer
744 views

Enterprise Anti-virus for Linux?

I know this question is probably at risk of offending the guidelines but our IaaS provider was unable to offer us an anti-virus solution for our Linux servers. We are deployed in an enterprise cloud ...
4
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3answers
323 views

Is it possible to USB whitelist in Linux?

After watching Black Hat's presentation on the fundamental problems with USB "security", I'm wondering if there's a way to do USB whitelisting in Linux. Is there currently a mechanism that will allow ...
0
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3answers
91 views

Permissions security scenarios for a web server

Having /var/www/site.com owned by www-data:www-data with a 750 permission for directories and 640 for files, and having my user alexb added to www-data group, I found my self with permission issues ...
1
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1answer
235 views

how to protect my linux pc from wifi sniffing

I have a wifi shared connection with other flatmates and I'd like to know how can I protect my Debian pc from being sniffed. Should I use a wifi anti sniffer to detect if any wifi card is in ...
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3answers
144 views

Is MS Windows more secure than Linux on this aspect?

The administrator account can be renamed which means the hacker needs to figure out two pieces of information : the user name and the password while there is always one root account in Linux named ...
0
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1answer
49 views

Throttle network based on OS [closed]

What do I need to learn/know to throttle a clients network based on his/her operating system. For example: Someone in my network using Kali Linux... I would like to throttle their traffic to ...
1
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2answers
88 views

Is it safe to create live usb on an infected system?

I am using Ubuntu 13.10. If my laptop is infected with malware, can I get rid of it by creating a live usb on it and using that live usb format and re-install the ubuntu ? I mean is it possible that ...
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2answers
290 views

Does the EICAR test work on Linux based antivirus scanners?

Does the EICAR antivirus test work on antivirus scanners for Linux? The EICAR test is described in more detail here: http://en.wikipedia.org/wiki/EICAR_test_file The reason I ask is that it requests ...
27
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5answers
5k views

Is Linux really that secure, with only root password denying external access?

While I was searching online for information about Linux security, the most typical explanation was: Linux is secure, because the root password is required to access the kernel and install new ...
1
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1answer
58 views

How to fuzz shared objects?

I know there have been similar questions about that topic, but I think mine differs from the others. I have this application which I am able to crash, but the error seems to happen inside of a shared ...