I've heard of attacks using PDF files on Windows with Adobe Acrobat and Foxit Reader. Is Linux vulnerable to these attacks when using the default PDF viewers in KDE or Gnome or even xpdf? What is a good PDF scanner to determine if a PDF file is evil?
View 2 RepliesIs Linux vulnerable to Java drive-by exploits? Another computer I run on windows 7 just notified me that it was infected through Java, and I'm wondering if my Linux box (ubuntu 10) with Java installed is vulnerable.
View 1 Replies View RelatedI have a VPS with Ubuntu. I host a small website (~10 visitors at the same time). Sometimes the website starts lagging. It lags so bad that my SSH connection starts lagging too. Running top says that 2 instances of apache2 take up 50 %CPU each.
I assume this is a DoS attack. I've copy-paste installed a few iptables scripts that made sense, but this has not helped. I installed libapache2-mod-evasive -- I'm sure it blocks the attacker, but I'm still lagging.
What can I do? Can I at least find the IP of the attacker? I have strong experience with Linux, but almost zero experience with being a server admin.
I have a mail server running RHEL, with postfix, dovecot, etc. I installed Fail2ban and this works wonders against SSH brute force attacks. It'll ban an IP address for a period of time if it unsuccessfully attempts to log on 3 times within, say a minute. I was wondering if it can be as effective with pop3 attacks. If it is, how can I get it done?
View 1 Replies View Relatedwe are using linux email server axigen past few years. we keep port open ssh and pop,smtp webmail etc. ssh use for remote trouble shooting. so through firewall it is globally accessable. we notice many attacks coming to our machine, also some people try to enter in our system but failure. as example see below a log come in messages file
Mar 17 09:19:50 sa1 sshd(pam_unix)[21231]: authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=210.51.13.120 user=root how we can secure more. as per my understanding only good long strong password can stop to prevent from attacks.
My laptop is beginning to show its age so it may be time for a new PC soon, and most likely it'll come with Windows 7 preloaded. I currently run a dual boot with Lucid and Windows XP, and although I hardly use XP anymore I would repeat this configuration on the new PC. So now I'm wondering if Windows 7 is any less vulnerable to viruses and malware than its earlier predecessors because I don't plan to renew any virus checking software that may come with it.
View 9 Replies View RelatedI installed lampserver and took measures to see that apache would only serve 127.0.0.1 (Which appears to be a software switch as ipconfig says it's port is still "Open")
Mysql however, could be vulnerable: Do I need to secure it or does it only serve localhost? If so, how do I secure it?
In the wake of all of the stories about the Windows DLL hijacking bug, it appears that certain Linux distributions may be vulnerable to a similar problem related to the way that Linux handles a specific variable in some cases. The bug apparently was introduced via a Debian patch last year.The discussion on the possible bug in Linux began with a blog post by Tim Brown, a UK-based security researcher, who detailed a specific case in which Linux could be vulnerable to an attack similar to those designed to exploit the Windows DLL bug. The post spawned a related discussion on the Full-Disclosure mailing list, in which several others confirmed that they'd seen the problematic behavior in certain Linux distributions, including Fedora, Ubuntu and Debian.
View 1 Replies View RelatedI have been reading about this new Firefox extension that can grab Twitter account information of computers connected to unprotected networks. Info: url
I occasionally have to connect to public, unprotected, WiFi networks and use Twitter via Gwibber. So, here is my question: is Gwibber vulnerable to Firesheep in an unprotected network? Is there a way of protecting it from this attacks? (I know that using https stops Firesheep attacks to the web version of Gwibber, but i don't think if this method is possible or applicable to Gwibber)
CentOS using yum to update Exim. Exim is configured to not allow remote connections using the local_interfaces config option.My old version was 4.63-5.el5_5.2 and after using:
yum update exim
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?
View 1 Replies View RelatedI'm using Debian 6 to host a website (with apache2) and a game server. But because of attacks to my server, my hosting company have now set it offline.
These are the two logs that they provided (I replaced all IPs):
Direction IN
Internal ***.***.***.***
[code]....
I was just wondering if you were to get DDoSed/Dosed would ubuntu block the packets or protect you in some way?
View 1 Replies View RelatedI fear that an attack or an entry in my PC has occured, how to find the trace of the attacks.
View 3 Replies View RelatedI'd like to set up a fileserver for myself and a few trusted individuals. I'm computer savvy and I use various linux servers frequently for work, but this is my first time trying to setup my own. Is it possible to have a Samba server setup so it is both secure and facing the Internet? Two questions:
Will opening Samba ports make my default Ubuntu server particularly vulnerable to penetration? More than having an SSH server running? Does Samba/ can Samba be configured to encrypt traffic or is it sent plainly? If so, does Windows and Mac support this secure communication?
If not, what would you suggest? I'd like to achieve something like a network drive and at a difficulty level that my parents could use this if they really wanted to. I will be storing things like financial information and tax returns, but no weapons-grade secrets.
I have a VPS which is running HTTPD, and its getting blown to bits by a DOS Attack. Turns out mod_evasive is totally useless (due to not running a total - rather counting per child process) and the only way to stop the box from running at 100% on all cores is to term HTTPD. So, what rules can I implement on the iptables firewall to block multiple requests from an IP? I saw this: [URL] Where someone has posted some rules but these dont work ("unknown error 4294967295" on the 3rd line). This is what i'm after though - block multiple requests from a single IP for a certain period of time.
View 3 Replies View Relatedrecently my Apache server crashes very often; by watching the error log,I've notice several signs of intrusion.So, I think the problem can be a denial of service attack against my machine.My distribution is Debian Lenny.
View 2 Replies View RelatedI'm trying to implement this method to block php injection attack using fail2ban: here it is, however I'm not sure it applies to Ubuntu. You see, there's this filter that must be added to the fail2ban jail file:
HTML Code:
[php-url-fopen]
enabled = true
port = http,https
filter = php-url-fopen
[Code]....
Given that my public key is a pre-shared secret is sshd made in a way that this negates the possibility of a man in the middle attack? In other words, if the known_hosts file were to be deleted, would it be safe to ignore the fingerprint of a server that already has my public key in authorized_keys?
View 5 Replies View RelatedWith the disappearance of an OS monoculture, attackers would do well to find attacks that are neither OS or application specific. One way to do that, of course, is to target attacks at hardware, rather than software. Now research out of Frances Ecole Superiore d'Informatique, Electronique, Automatique (ESIEA) moves a step closer to that goal: identifying a method for isolating the processor used by anonymous systems for the purpose of subverting that hardware.
View 2 Replies View RelatedMy server has been the repeated victim of bandwidth attacks: any large file on the server is downloaded repeatedly, with the goal of pushing the server over the provider's bandwidth limit. How can I lessen the effect of these kinds of attacks with IPTables or APF? For example, can I set the server to: Is this possible? Is there a more effective way, and can a firewall even do this? My web server is Lighttpd, perhaps I can place such a rule directly in its config?
View 1 Replies View RelatedMy debian server has been attacked due to a security breach in exim4 4.69-9 (probably applies to loads of other versions too). The security breach allows the attacker to get root access by creating a buffer overflow in a header which then can be used to inject code.
[URL]
The securtiy breach is fixed with 4.69-9+lenny1 I want to share my actions with you on what I did to (hopefully) get rid of it. However at the time of writing this, the above website is down due to too much load (DDOS Attack?). How you can check if you've been attacked:
The attack creates a buffer overflow in exim4, which results in paniclog entries.
$ cat /var/log/exim4/paniclog
2010-12-17 07:34:11 string too large in xxxyyy()
2010-12-19 10:42:10 string too large in xxxyyy()
this would be an example of two attacks. One on 2010-12-17 and the other two days later 2010-12-19.with this information you can start find potentially infected files. There may be a better way, but I searched for them with this command:
$ find / -mtime 31 2>/dev/null # files,directories,links created 31 days ago (i.e. 2010-12-17)
My infected files:
/usr/bin/uptime
/usr/bin/pwdx
/usr/bin/slabtop
[code]....
I need to learn how to analyze network traffic for attacks and while finding the attack seems easy in my case I need to identify what hes doing. I will be happy right now if you guys can answer my question. How to identify if an attack has brought the server down? I have packet captures of an attack in progress and I noticed that every now and then the attacker would do something weird and the server would start sending packets with just the RST packet sent in response. Normally I had been seeing the RST ACK flags set or the FIN ACK bits set to terminate a connection. So once again my question is how do I tell if the traffic indicates a server crash?
View 1 Replies View RelatedI launched my website. At the moment the site has an firewall (iptables) enabled with very simple rules. All incoming traffic is blocked, except for the ports http and ssh. Everything is working perfect, but I want also to be able to block certain kinds of attacks. There are some really good examples on the internet, but I don't now if they contain all kinds of attacks which are relevant to my situation. To be clear, I only server web content through port 80 and use ssh to remote login.
View 3 Replies View RelatedI used Avast webfilter (proxied webtraffic through Avast) when running Windows. Sometimes Avast would alert and "protect" me from being infected by a compromised website. NOTE: Avast would alert even absent clicking any links. Just viewing the page could result in infection. Should I be running some kind of proxy webfilter for protection? My understanding is that Firefox can be compromised and this can in turn compromise Ubuntu.Are these kinds of threats specific to Windows running Firefox, or Firefox per se. If Firefox per se it seems like I need some sort of Proxy webfiltering like Avast provides.
View 9 Replies View RelatedI have a SSH server set up at home listening on port 22. I have hardened the server so it is pretty secure but I want to make it even safer by editing my iptables to rate-limit incoming connections and DROP false login attempts. I have tried these tutorials but I just cant get it to work:[URL]I want the debian-administration.org tutorial to work but when I try to add the first rule in terminal:sudo iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent --setI get the following:Bad argument --set'I am new to iptables and I'm not sure if I'm doing something wrong when I try to set it up. I'm using Ubuntu 10.04.1 LTS with iptables v1.4.4.
View 6 Replies View RelatedI need to do a pentest on a Microsoft IIS webserver to test the efficiency of the HIPS i have installed on. methods to simulate attacks so that i can check if the HIPS will detect them?
View 4 Replies View RelatedI am ashamed that I am causing other people troubles, but apparantly my server is involved in attacking the servers of other people.
I have to admit that I am not too familiar with using a CLI, or Linux for that matter, but I have a Debian server running under Plesk 10, which is colocated.
Now I have received messages from the datacenterm which state that my server is involved in brute force attacks.
The messages show a lot of lines like this:
Code:
The only I get from my hoster is to back up all domains and re-install the machine.
I want to resolve this asap, but do not agree with that action for two reasons: the machine just had a fresh re-install 2 months ago, so if it is a flaw in the OS, I will get the same flaw back, and if it is not OS related but due to a domain, I will get the problem back by putting back the backed-up domains.
But now I'm stuck: what steps should I follow to try and find the cause of this evil and make sure that my machine will not bother other machines anymore?
I realize that this probably will be a steep learning-curve, but please bare with me and help me to resolve this.
What have I done so far?
1) There are a number of live sites on this server, either running WordPress or Joomla, I have made sure they are all updated to the latest release.
2) I have manually looked at the source code of the index-files of those sites, haven't seen anything strange, like redirects.
3) I have used online scanners to check all sites for malware, all have been reported back to be clean.
4) I have run the Plesk-version of RKhunter, and that gives me certain warnings which I cannot (or do not) understand:
Code:
Code:
Code:
I received the first report of these attempts about a week ago and immediately changed the Plesk/SSH password to a 200bit password generated with KeePass, hoping that would keep out any evildoers.
I'm just curious as to what security measure's I should be taking to make my box a little less vulnerable? I'm still experimenting/playing with Linux, use the net, IM, download this and that and was wondering how secure fedora 10 was out of the box?
View 12 Replies View RelatedMy Ubuntu system is occasionally becoming very sluggish. I'm running many things simultaneously and it's very difficult to tell which program is the culprit.
I suspect that the sluggishness is due to disk activity since the CPU usage is consistently under 50% on each of the 4 cores of the CPU, and over 30% of the 6GB of RAM are free.
Is there a tool that can show me in real time the number of disk IO operations per second and the amount of data read/written per second? Can all this info be broken down and displayed per process?