Content related to computer security., i.e. content about policies, mechanisms, etc. needed make sure data is not leaked or corrupted and services available in all circumstances.

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3
votes
1answer
66 views

How come I can login to another person's session over vnc just by changing the port number?

I have a user account on a server administered by someone else. I don't have root access. The server is CentOS 7. I couldn't connect over vnc on the usual port I use, so I ssh'd into the server and ...
3
votes
2answers
1k views

How can I install Linux on a UEFI system with Secure boot?

My motherboard is a Gigabyte 990XA-UD3 (CPU 1), it's a UEFI -Dual boot, and when I try installing Linux Mint 16 Cinnamon or Ubuntu 13.10 it always bring this error (initramfs) Unable to find a medium ...
16
votes
2answers
1k views

Vulnerability demonstration on Ubuntu 9.04

For a class on IT security, I want to demonstrate privilege escalation to the students. To do so, I looked through the exploit/linux/local list in the Metasploit Framework, finding (among others) ...
6
votes
3answers
5k views

Write to a file without redirection?

I am writing a regular compiled application that needs to create a special file and write a magic cookie into it. I can’t write the file directly from the application, the system security model ...
6
votes
2answers
7k views

How do I disable remote root login via ssh?

How do I disable remote root login via ssh? I want to log into my server (I use keys on my main comp) then su into root instead of access root directly. I am using Debian. I follow guides online ...
4
votes
1answer
796 views

Running unsigned javaws code

For a KVM remote console I need to be able to run a jnlp file. When I run it I get: net.sourceforge.jnlp.LaunchException: Fatal: Initialization Error: Could not initialize application. at ...
-2
votes
5answers
119 views

Why does superuser exist in Unix/Linux?

I know that some system tasks are permitted only to privileged users/processes, but still a super user (usually the root in Unix/Linux) or administrator can present so much problems in regards to ...
1
vote
1answer
15 views

Filebased SELinux booleans

I'm trying to get numba running on my Debian server in SELinux enforcing mode. Numba is build on LLVMs jit compiler. The problem is, LLVM insists on having memory, which is writeable and executable at ...
17
votes
4answers
38k views

Moving /var, /home to separate partition

I am attempting to move some folders (such as /var and /home) to a separate partition after reading this guide: 3.2.1 Choose an intelligent partition scheme I was able to move one folder ...
3
votes
1answer
52 views

Why is chroot(2) unavailable to unprivileged users?

Why is chroot(2) unavailable to unprivileged users? I don't understand existing answers on the Internet. For example this one ...
1
vote
1answer
46 views

linux + yum update - what this command covers?

I verified what are the missing security patches as the following: yum updateinfo list security available Loaded plugins: product-id, rhnplugin, security, subscription-manager This system is ...
0
votes
0answers
26 views

Possible improvements to script that runs golismero security scan crash-safe?

I am trying to do it this way. Due to some issues with golismero that causes more crashes then I'd prefer, I use a workaround suggested by the dev team and saves all found items to the db - and if it ...
1
vote
0answers
32 views

Automatically manage whitelisting (e.g. in tinyproxy) of dynamic IPs?

I have a VPS that runs tinyproxy for private use, and another that runs nginx for development. Is there a protocol/daemon that I can use to automate whitelisting for my dynamic IP? So that tinyproxy ...
6
votes
3answers
2k views

BCRYPT - Why doesn't the Linux Distributions use it by default?

Does OpenBSD use bcrypt by default? Why doesn't every modern Linux Distribution use BCRYPT? http://codahale.com/how-to-safely-store-a-password/ https://secure.wikimedia.org/wikipedia/en/wiki/Bcrypt ...
-2
votes
3answers
66 views

Is a fresh install of linux equivalent to a honeypot? [closed]

Hello I was wondering whether a a fresh install of Debian connected to the internet without further protection (iptable or whatever) is safe or equivalent to a honeypot. Do we have some people that ...
4
votes
0answers
35 views

LXC: Any security difference between root and end-user owned unprivileged containers?

I intend to use LXC containers to isolate most of the network facing services. As per my understanding, I have mainly two ways to do this: Create unprivileged containers owned by root. In this ...
0
votes
0answers
61 views

OpenVas + Kali Rolling: The connection was reset

I am trying to get OpenVAS to work in the latest Kali release (rolling). It seems to be installed right, but when I try to access the web interface (127.0.0.1:9392), I get Connection was reset. ...
1
vote
1answer
27 views

Block regular users from changing their passwords: only root should be able to [closed]

For security reasons, I want to make it so that only root can change user's passwords This can be achieved if I set /usr/bin/passwd to 700. Now, if password aging is enabled or first login is enabled, ...
0
votes
1answer
16 views

wget TLSv1 behaves the same as TLSv1_2

I used wireshark to compare curl --tlsv1.0 vs --tlsv1.2 The server handshake obediently uses TLSv1.0 for servers that support it (the point is to check to validate they don't): wget url ...
1
vote
0answers
21 views

Selinux inode security struct allocation

i'm trying to understand allocation of inode_security_struct in Selinux. I looked for a source code of selinux and there is only one allocation of this struct on line 230 in hooks.c file. This ...
1
vote
1answer
38 views

Is Evince a secure way to view malicious PDF?

I've seen that PDF's can contain malicious Javascript that operates in the background and can do bad things. This is primarily a problem for Adobe Acrobat. However, is this problem also for Evince? I ...
1
vote
1answer
41 views

Restrict login via user group in access.conf

I have been working on getting /etc/security/access.conf to work as expected and so far every user can still login. Details are below. I added the following line to /etc/pam.d/login account ...
0
votes
0answers
24 views

Install ModSecurity Commercial Rules

We bought the ModSecurity commercial rules, but I am not having success installing them. I tried using the ModSecurity dashboard, but it seems that it is not working. Even though I get a message ...
3
votes
1answer
42 views

Brute force attack on vsftp server not showing failed authentication in log

My server is running Debian 8 with vsftpd version 3.0.2-17. Recently my vsftpd.log filled up with the following: vsftpd.log Mon Mar 7 18:13:44 2016 [pid 13499] CONNECT: Client ...
1
vote
1answer
52 views

Is there a way to resolve ALL PIA VPN IPs with a script?

I am looking for a way to get a complete list of all the current IP addresses for PrivateInternetAccess' servers. I need the complete list so that I can manually enter them into a killswitch for ...
2
votes
3answers
2k views

SUID permissions - Which is correct?

Trying to secure a Linux server and have little experience with SUID. After executing find / -perm +4000 many programs were discovered. I have seen conflicting advice here and hereon what should ...
-1
votes
1answer
90 views

Bash Code Injection Vulnerability On Linux

Found a bug in Centos Linux, a bash code injection vulnerability. The solution to this is the update the bash package. yum update bash My Question is "do I need to reboot the system"? We ...
0
votes
6answers
181 views

Linux Mint: I'm infected with a rootkit

I tried logging in to my admin account and it said password incorrect. There is no way it could have been incorrect since I copy-pasted it from a usb drive. I reset my password, installed chkrootkit ...
2
votes
2answers
86 views

Avoiding plain-text password in http_proxy

I am behind a corporate firewall, which brings lots of pains in the area of proxies. There are two main approaches I've found to work: Use Cntlm at the cost of not being able to connect (from the ...
0
votes
3answers
53 views

Why does reading a device require admin permissions?

I'm trying to create a backup script that saves my thumbdrive as an image. I'm planning on having it automatic. I've always seen the thumbdrive listed as /dev/sdb, and created a script that will save ...
0
votes
0answers
12 views

Adding IP Blocklists to OSSEC

I've been reading through some documentations for OSSEC trying to learn some new tricks and such to make it more effective, and what I got really interested was looking into was seeing if it's ...
4
votes
3answers
128 views

What exactly differentiates the root user from every other user?

What are the fundamental differences between some arbitrary account and root? Is it just the UID being something other than zero? So, what exactly does the su binary do and how does it elevate a user ...
30
votes
8answers
2k views

Can malware run by a user without admin or sudo privileges harm my system? [closed]

After a recent break in on a machine running Linux, I found an executable file in the home folder of a user with a weak password. I have cleaned up what appears to be all the damage, but am preparing ...
14
votes
3answers
24k views

How can I block a range of IP addresses with an Amazon EC2 instance?

I know a certain range of IP addresses are causing problem with my server, 172.64.*.* what is the best way to block access to my Amazon EC2 instance? Is there a way to do this using security groups or ...
2
votes
2answers
1k views

Ghost Vulnerability On Linux

It came to our notice that glibc needs to be upgraded from the current version 2.2 to the latest as per the release 5/6/7. My Question is that do I need to reboot the system, because we are having ...
2
votes
2answers
50 views

Would draining entropy make it easier to compromise a system? [duplicate]

Entropy is important for many security features like TCP sequence numbers and cryptographic key/parameter generation. My understanding is that the entropy pool is drained by an operation as simple as ...
1
vote
0answers
127 views

What is the command erepc? Is this malware?

I noticed that my system was running slower than normal so I ran a top command. Hogging a ton of my CPU was a process called erepc that I can find no information on. PID USER PR NI VIRT ...
1
vote
2answers
22 views

Are there sandboxing concepts for proprietary binary kernel modules in linux?

Quite a lot has been going on to advance inter-process security (UID the same) and priveledge dropping in userland, yet it is common that proprietary linux kernel components are used (it seems that ...
0
votes
0answers
46 views

Does the following error indicate my system is compromised?

[FAILED] Failed to Verify Integrity of password and group files. See 'systemctl status shadow.service' for details. I get this message in T1 every time I start up the computer but I havn't noticed ...
3
votes
2answers
51 views

Why are privs required to setgid() to supplementary groups

The various set*gid() system calls require privileges to change groups except in a very few cases. Changing primary group to one of the processes' supplementary groups does not appear to be one of ...
0
votes
0answers
7 views

How to permanently set a password for ipaserver client accounts

I want to setup a password for RHEL/Centos ipaserver client accounts but it seems I have to keep manually resting it on the ipaserver host. Is there a way to persistently set it?
1
vote
1answer
50 views

How to write a file a file via ssh

I want to write a file in the Machine B under /home/test whose permissions are root:root and rwxr-xr-x. I have an account on the Machine B, named testUser. When logged to the Machine B with ...
1
vote
2answers
26 views

Whats the difference between adding scripts in the /etc/cron.daily/ or editing in your script in crontab(-e)?

There are multiple options - with cron - to start your script at a specific time, but, is one more secure over the other? My question is simple: Whats the difference between adding scripts in ...
8
votes
1answer
190 views

Is there a technical reason why ssh-agent lacks a sudo-like inactivity/idle timeout feature?

There are some brief discussions about the existing ssh-agent -t feature at [1], and there was a post as far back as 2001 on debian-devel [2] wishing for an inactivity timeout feature. There's a ...
0
votes
3answers
81 views

How to stop a user from seeing command line arguments?

We have a CI server application run as the build user. Any command with arguments run by the CI server is visible via ps. Although non-admin users do not have access to load a shell on the CI server, ...
2
votes
1answer
1k views

Any better alternative to chroot on an OpenVZ VPS?

Are there any better alternative to chroot environment? I'm thinking about running nginx on a jailed environment. BTW, I'm on OpenVZ VPS, so modifying the Kernel is a no-no. (I think that prevents ...
0
votes
4answers
1k views

noexec on /tmp and /var/tmp directory

Our client servers are running old version of jboss (Jboss 4.0) which has lots of known vulnerabilities. Result is that the server is hacked and we are seeing some unknown executables running from ...
15
votes
1answer
846 views

Why can I list other users processes without root permission?

Using ps -aux or top, I can list other users running processes, but i'm neither running as root or making use of sudo, why ?
1
vote
3answers
192 views

MySQLdump via crontab - Pass --password=/hashed/password/file so I can use via crontab w/o using plain text password

So I'm setting up a WordPress backup guide/making a backup schedule for myself for real. I want to do MySQL dumps daily, but the command either requires -p then user input or ...
-5
votes
5answers
550 views

Since Android has malware, does it mean no Unix is immune from malware?

Android has virus: Android.Counterclank, Android.Tonclank (seal info, back-door). Does it prove that FreeBSD, Solaris, Fedora, CentOS, ArchLinux, Ubuntu all is running and having similar ...