Security :: Centos 5.5 Server - How To Protect From Outside Attack

Dec 21, 2010

I have just configured Centos 5.5 LocalMailServer with fetchmail and sendmail , Proxy with Squid and FileServer with samba. Now my concern is security.. How can i protect my server with outside attack. Will I need to block some ports or I need special tools or script so no one from outside can attack my machine. My machine is working on intranet with local ip only.. No web server or static ip exists. Machine is connected with ADSL router to access internet.

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Server :: Protect My Server From Syn Attack ?

Jun 15, 2011

I want protect my server from syn attack

My server Linux - Cantos 5.6.

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Ubuntu Security :: Best Solution To Protect Server From Security Threats?

Jul 22, 2011

I've recently been running a game server from my desktop, as well as a web page to accompany it.I use the ports 80/8123(HTTP)/5900(VNC)/50500(GAME)/5839(ADMINISTRATION).What's the best solution to protect my server from security threats? On a side note, I plan on adding a MySQL server later, but I want to keep it local only.

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Security :: Track DDoS Attack On A Server?

Jan 25, 2011

how can I track a Dos and DDoS attack on a server . Does linux have any goiod known command line utilities and log files to us e in this way?

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Fedora Security :: Server Seems To Attack The World Hacking?

Apr 10, 2009

I went away from home for a few days, ... Now I am back at home and noticed, that my server is going out with 100% available bandwidth. The server is mainly Http / Ftp / Mail server, so I stopped all services, to see which one it is. ervices stopped, still 100Mbps go out like ants in the flood.

I updated the system, made a backup, installed IPtraf. It seems that I have something 'installed' and my server is running something to attack User computers. It seems to try to find something on random IP's random ports. I am a little bit confused now. As long as my sites are running, I'm ~OK~ but sooner or later I would like to have my bandwidth back. How could I try to hunt down which service/app/process got hacked?

It seems that the monetary system of our society got now more enemy's than friends. Capitalism seems to reach it's end. But my server is serving also ART! Sooner or later we will need to pay copyright even for our thoughts. I was reading today, that the French president wants to punish file sharing as his wife made 3 albums, and wants to get some money ..

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Security :: Protect Server From Url Injection?

May 20, 2010

I am facing problem on my Linux server, those runing php sites, most of the time hacker upload file in my website and take the control, and hack the sites, shoot the thousands of mail etc

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Security :: Is Server Under DdOS Attack - Not Having Much Load And Only Few Process Runs But Site Opens Very Slow

Aug 5, 2010

I have a server and i think that my server is under Ddos attack. i see that server is not having much load and only few process runs but my site opens very slow. i executed the following command on my ssh:

[Code]....

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CentOS 5 Server :: Tracing An Attack With A Wireshark Script

Jun 18, 2009

My data center informed me that my shared web hosting server is producing a massive attack. Attack against who? how? etc?... well.. other than "your server is generating an attack of over 150,000 UDP connections", they did not specify the target IP, nor the specific port. The attacks usually run for less than 5 minutes and pose a threat on the datacenter's firewall itself (from within).

I ran various searches on my server and came up with nothing. (over 300 websites with PHP in 25GB of data, database etc).

I do not allow any shell/bash other than myself, so no other logins are available. (I re-checked /etc/passwd for any bash).

I believe that there is probably some php fsckopen call or something to that degree that responds to a call from an external server. To make it easier to diagnose the problem and then stopping it, I need your assistance developing a simple tracing tool, methodology.

I have wireshark installed on the server.

My thoughts on how to capture this attack (which occurs at random) is as follow:

1. run a service that greps and count the UDP connections currently on the server and does this every 60 seconds. ( a simple one minute cron is enough).

netstat -a |grep UDP -cw

2. Currently the output shows: 0 (zero).

3. I do run a DNS server that can be queried, so I expect to see some UDP calls every so often. However, this is probably going to occur at < 50 entries.

4 . run this logic if no high loads on the server.

If servers load is < 3.00
{
If ( netstat -a |grep UDP -cw ) > 50
{
./tshark > wireshark.hacker.trace<timestamp>.txt;
email me an alert that "hey wireshark was triggered";
sleep (15)
killall -9 tshark
}
}

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Security :: Protect Samba Server For Limiting Access To Certain Domains?

Nov 24, 2010

I was looking for a way to protect my samba server for limiting access to certain domains.Can I use the parameterhosts allow = example.comor something like that or is there another way to do the job for domains

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Security :: NSA On Computer Network Attack & Defense

May 3, 2010

Quote:

The 605-page PDF document reads like a listing of the pros and cons for a huge array of defensive and counterintelligence approaches and technologies that an entity might adopt in defending its networks. Of particular interest to me was the section on deception technologies, which discusses the use of honeynet technology to learn more about attackers´┐Ż methods, as well as the potential legal and privacy aspects of using honeynets. Another section delves into the challenges of attributing the true origin(s) of a computer network attack.

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Security :: Sample Attack On Honeypot System?

Nov 23, 2010

I have implemented two machines one for honeypot(192.168.100.10) and another(192.168.100.20) to remotely log the honeypot log file using syslog. Inside honeypot I emulated another 3 machines with services on virtual IPs of that same block.Now honeypot is working and I can see the logs generating as I did a portscan(nmap) on those virtual IPs from .20 machine.All of the machines are running ubuntu.

But does anyone know any s/w or tools which originally attackers use so that I can get a clear picture of what happens from the logs. Having problems creating these attack scenarios.

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Security :: Program To Stop DDOS Attack?

May 30, 2011

i have 1 question no more because i got many ddos attack and my load is 95++ what is the best program to stop DDOS Attack ?

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Fedora Security :: Attack Sneaks Rootkits Into Kernel

May 7, 2009

Attack Sneaks Rootkits Into Linux Kernel Quote: A researcher at Black Hat Europe this week will demonstrate a more stealthy way to hack Linux

Apr 14, 2009 | 04:21 PM
By Kelly Jackson Higgins
DarkReading

Kernel rootkits are tough enough to detect, but a researcher this week has demonstrated an even sneakier method of hacking Linux. The attack attack exploits an oft-forgotten function in Linux versions 2.4 and above in order to quietly insert a rootkit into the operating system kernel as a way to hide malware processes, hijack system calls, and open remote backdoors into the machine, for instance. At Black Hat Europe this week in Amsterdam, Anthony Lineberry, senior software engineer for Flexilis, will demonstrate how to hack the Linux kernel by exploiting the driver interface to physically addressable memory in Linux, called /dev/mem.

"One of bonuses of this [approach] is that most kernel module rootkits make a lot noise when they are inserting [the code]. This one is directly manipulating" the memory, so it's less noticeable, he says. The /dev/mem "device" can be opened like a file, and you can read and write to it like a text file, Lineberry says. It's normally used for debugging the kernel, for instance.

Lineberry has developed a proof-of-concept attack that reads and writes to kernel memory as well as stores code inside the kernel, and he plans to release a framework at Black Hat that lets you use /dev/mem to "implement rootkit-like behaviors," he says. The idea of abusing /dev/mem to hack the Linux kernel is not really new, he says. "People have known what you can do with these /dev/mem devices, but I have never seen any rootkits with dev/mem before," he says.

Quote: "The problem with kernel-based rootkits is that the rootkit can mitigate [detection] because it has control," he says. "It's a race in the kernel to see who's going to see who first." [URL]

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Fedora Security :: Cold Boot Attack Prevention

May 13, 2009

I have full hdd encryption with a rather long key. The thing is the FBI might just show up at my house one day and have a warrant for my PC, and who wants the government looken through there life? I have a few plans on geting my PC shut down before they can get there hands on it. This is all well and good, but if they can sniff my key from the ram It doesn't matter what my key is or weather they find the computer on or off. Anyhow, i was wondering if there was some way I could add a script to the shut-down process that would over-write the ram.

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Fedora Security :: SE Attack Alerts - Root Out The Source?

Oct 20, 2009

I have been receiving attack alerts. And I would like to root out the source of the problem. I'll give you the messages. If you could help me prevent this hacker from even being able to attempt these things please any advice is helpful. There have been memory stack attempts, failed sys_admin conversion attempts, password file write attempts etc.....

[Code]...

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Ubuntu Security :: HD Attack Into APT Manager And Folder Permissions

May 24, 2010

I may not be a code worrior, yet I have been a Ubuntu convert from Apple for about 3yrs now. Since 1984-2006 now hackers or viruses. And Until now Ubuntu has been clean, well I have been good with repos, etc.

1. Recently I found "Odd" behavior with my Amarok 1.4 player, ffmpeg, winff.

2. During a Synaptic upgrade there were some "unauthorized changes". I have seen this before due to some of my software, so I ignored it. . .

To my bewilderment, "It" erased Amarok 1.4 player, ffmpeg, winff, all image kernels, claimed domain over my system permissions, and external HD. B4 I shutdown, downloaded LUCID 10.4. . . restarted, then copied over all info possible to minimize a complete delete of my system. Upon restart, indeed all kernel images were gone, Only live CD allowed me access to repartition my HD.

NOW. I have Lucid running, and have been denied access to my external HD and partitioned (internal HD). I used Nautilus to copy over files to my internal laptop HD, yet permissions continue to be an issue. The INFECTED FOLDERS are owned by "User 999-user#999. I must micro manage every folder and file to gain "partial permission". The dialog box stutters and never allows me to go down to "Root"

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Ubuntu Security :: MITM Attack - TLS Renegotiation Vulnerability

Sep 28, 2010

Using Opera 10.61 and 10.62, I find that any secure website I access, such as a bank, the lock icon in the address bar is replaced by a question mark. Clicking on it brings up a window, stating that the connection is not secure, that the server does not support TLS Renegotiation. Doing some internet searches for "opera tls renegotiation" brought me to a page at the Opera website, where they discuss this issue. The issue is generic, not limited to Opera, affecting the TLS protocol, and it potentially enables a man-in-the-middle to renegotiate a "secure" connection between a server and client, issuing own commands to the server. Opera has addressed the problem on the client end, but now servers need to be upgraded too. None of the HTTPS sites I have tried have upgraded their servers, if the information provided by the Opera browser is correct.

My questions: how feasible is such a MITM attack, what level of resources would such an attack require? What, if anything, would the attacker need to know about the client and/or server to mount the attack? Would I be better off using Firefox, or is Firefox simply oblivious of the problem and not issuing warnings for that reason?

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Ubuntu Security :: Broke Into Computer - Verify Attack?

Dec 28, 2010

mpg123 suddenly started playing a police siren occationly. I checked the process once I heard it, and root was the process owner. How could this happen? Have someone broke into my computer? If so - how could I verify an attack? I run Ubuntu 9.10.

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Security :: How Does Mktemp Prevent Denial Of Service Attack

Apr 22, 2010

This is an excerpt from the Linux man page for mktemp command: "mktemp is provided to allow shell scripts to safely use temporary files. Traditionally, many shell scripts take the name of the program with the PID as a suffix and use that as a temporary filename. This kind of naming scheme is predictable and the race condition. It creates is easy for an attacker to win. A safer, though still inferior approach is to make a temporary directory using the same naming scheme. While this does allow one to guarantee that a temporary file will not be subverted, it still allows a simple denial of service attack. For these reasons it is suggested that mktemp be used instead."

- How can a denial-of-service attack be carried out if a directory name is known?
- Why is it important to use mktemp to generate a sufficiently random file/directory name for temporary files?

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Ubuntu Security :: Firestarter Howing Attack From Samba Service

Mar 17, 2010

I got alarm on Firestarter showing attack from samba service on port 139 . Is that ok for my host computer ? or a serious attack .

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Security :: Attack Warning In Logwatch Message: Loopback Relay

Dec 14, 2010

I'm not concerned about this since this traffic is generated from the loopback address, but would like to find out what it is.

[code]...

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Security :: HOW TO Protect From VPN Attacks

Jun 1, 2011

I would like to know how to protect networks against VPN attacks? How does big industries do it? What does the government tend to use? Are any tools open source that I may get?

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Security :: John The Ripper Brute-force Attack And Multi-core Processors?

Feb 19, 2010

In my Open-Suse server I have a script, where makepasswd output(by default it generates similar passwords: cGyTbqpr, tpJ1LA, 33EXdo) is redirected to mkpasswd(which uses DES by default) in order to generate salted hash of this previously generated password. I would like to test the strength of this system. I have a quad core CPU, and if I start John The Ripper like this(I want to use -incremental:all flag):

john -incremental:all passwd

..only one core is utilized at 100%. Is there a possibility to make all four cores to crack this password? Or is this possible only after reprogramming John The Ripper? Or what is the algorithm for generating passwords with with -incremental:all flag? I mean if John generates passwords randomly in brute-force mode, then it's smart to start four different John processes simultaneously because then one of those four will find the password firs

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Ubuntu Security :: Does Firestarter Protect Out Of Box?

Sep 15, 2010

I was wondering if firestarter (software firewall) works out of the box or does it need some kind of configuration in order for it to provide protection? Is firestarter even needed with ubuntu?

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Fedora Security :: Trying To Password Protect Directory

Apr 1, 2010

I create music and usually gets sold world wide. I have some distributors that have been able to access a private server and get the new tunes I make to download via ftp. Well that server is getting full and I was trying to create another directory on my website itself.I created the directory. made the ".htaccess" file. Then I tried to make the htpasswd file but my server just keeps saying no command by that name.

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Ubuntu Security :: How To Protect From Untrusted Files

Oct 8, 2010

I want to start using videos/music files downloaded from untrusted sources (BT,Sharing Forums, etc.). Haven't made this a habit b4 because of the security risks. I want to take steps to reduce the risk & protect my computer from anything malicious. What are some good choices for this? The biggest step I took so far is using Ubuntu since it's very virus resistant, but other threats do exist out there (rootkits, malicious scripts, etc.). When downloading files from untrusted sources, who knows what may be hidden inside.Some options I'm thinking about:

1) Using a VM (with Ubuntu installed inside) & playing the files inside the VM. If anything malicious happen, it would be trapped inside & I could easily revert to a clean snapshot.

2) Using AppArmor to restrict what the files or program used to play the files can/can't do. AA seems very complicated though.

Are the above overkill? Would it be sufficient enough to just open these files on a non-admin user account since no access to root or sudo?

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Security :: Some Precaution Should Take To Protect Notebook From Intruders?

Jun 3, 2010

I am planning a trip for a few days and I will be staying at an inn with Wifi access. All the guests are allowed to use it. A friend of mine has been there, he told me there are several other private spots around the house, i.e. lots of other people using Wifi. My friend told me the inn uses WEP, so who knows how many times their access point has been hacked and accessed without permission...

My concern is that I will be there for a few days with my notebook, I will have to work once in a while, connected to the Internet. Is there some precaution I should take to protect my notebook from intruders? Is it advisable to install a firewall in my notebook (iptables?) or am I just overreacting? Is it possible for one of the guests or neighbors to break into my notebook?

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Fedora Security :: Programs To Protect My Computer On Internet?

Apr 29, 2009

are there any programs that will protect my computer on the Internet. Just started using fed 10 from windows so i am not sure what i need to do. I am using an acer aspire 5630 laptop.

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Fedora Security :: Password Protect File Folders?

Oct 12, 2009

I was wondering how to password protect certain file folders?

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Fedora Security :: Configure See To Protect The Contents Of A Folder?

Jul 28, 2011

im currently trying to configure SE Linux policy for a folder so that only my user with root privileges can access it and not just root but i don't know the commend to run on the folder to change its permissions

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