Infi-Zeal's Blog

 fork bomb is a denial-of-service attack whereby a process continually replicates itself to deplete available system resources. It can be prevented by limiting user processes.  Limiting user processes is important for running a stable system. To limit user process just add user name or group or all users to /etc/security/limits.conf file and impose process limitations. Understanding /etc/security/limits.conf file <domain> can be: an user name a group name, with @group syntax the wildcard *, for default entry the wildcard %, can be also used with %group syntax, for maxlogin limit <type> can have the two values: "soft" for enforcing the soft limits "hard" for enforcing hard limits <item> can be one of the following: core - limits the core file size (KB) <value> can be one of the following: core - limits the core file size (KB) data - max data size (KB) fsize - maximum filesize (KB) ...

Due to their nature, fork bombs can be difficult to stop once started. Stopping a fork bomb from reproducing further requires the termination of all running copies, which can be difficult to achieve. One problem faced is that a separate program to terminate the fork bomb cannot execute if the process table is fully saturated. The second major problem is that in the time taken between finding the processes to terminate and actually terminating them, more may have been created. Some fork bombs can be stopped relatively easily. Consider the shell fork bomb: : (){ : | : & } ;: By replacing the function identifier and re-indenting, the code reads: bomb () { bomb | bomb & } ; bomb The fork bomb in this case is a recursive function that runs in the background, thanks to the ampersand operator. This ensures that the child process does not die and keeps forking new copies of the function, consuming system resources. One important "featur...

The concept behind a fork bomb — the processes continually replicate themselves, potentially causing a denial of service C an you explain the following bash code or bash fork() bomb? :(){ :|:& };: The fork bomb is a form of denial-of-service (DoS) attack against a Linux based system. It makes use of the fork operation. :(){ :|:& };: is nothing but a bash function. This function get executed recursively. It is often used by sys admin to test user process limitations. Linux process limits can be configured via /etc/security/limits.conf and PAM. Once a successful fork bomb has been activated in a system it may not be possible to resume normal operation without rebooting the system as the only solution to a fork bomb is to destroy all instances of it. WARNING! These examples may crash your computer if executed. Understanding :(){ :|:& };: fork() bomb code :() - Defined the function called : . This function accepts no arguments. The syntax for bash fu...

Wikileaks has been under DDoS attack for the last three days The Pirate Bay is down. Wikileaks is down. Visa was down. Are all these Distributed Denial of Service (DDoS) attacks a coincidence? Right now it’s not clear, but something is definitely happening. After covering The Pirate Bay Distributed Denial of Service (DDoS) attack and Anonymous’ denial of responsibility for it, I’ve been checking the torrent site’s Facebook Page every so often. The Pirate Bay said it thought it might know who was behind the attack, so I was curious if they would post it today. They haven’t yet, but they did just post this: Wikileaks.org is also under attack. This sure is the year of the storm… As predicted here: https://thepiratebay.se/blog/204 I checked, and indeed  Wikileaks  is down for me. The site’s  Twitter  account sent this message out five hours ago: “WikiLeaks has been under sustained DDOS attacks over the last 72 hours. http://www.wikileaks.org is good, http:...

DOS Attack via Google Panos Ipeirotis, a computer scientists working at New York University, learned the hard way that Google can be used to launch successful denial-of-service (DOS) attacks against sites with minimal effort. On his  personal blog  Ipeirotis explained that it all started when he saw that Amazon Web Services was charging him with ten times the usual amount because of large amounts of outgoing traffic. “Initially I was afraid that a script that I setup to backup my photos from my local network to S3 caused that bandwidth. But then I realized that I am running this backup-to-S3 script for a few months now, and in any case all the traffic that is incoming to S3 is free. This is a matter of outgoing traffic,” he explained. After analyzing traffic logs he was able to determine that every hour a total of 250 gigabytes of traffic was sent out because of Google’s  Feedfetcher , the mechanism that allows the search engine to grab RSS or Atom feeds when use...

Indian computer security analysts have detected and alerted Wi-Fi  users in the country against a possible virus attack. Indian computer security analysts have detected and alerted Wi-Fi users in the country against a possible virus attack that could lead to crashing and hacking of secure networks. The Indian Computer Emergency Response Team (CERT-In), country's national agency to respond to computer security incidents, has found that the " Wi-Fi Protected Setup (WPS) contains a design error that could allow a weaker-than- expected defence against brute-force attacks, which could allow an attacker to gain unauthorised access to the affected system." A brute-force attack, in computer terminology, is a programme that is used to crack and stealthily enter into an encrypted and password protected system while WPS is a popular method for setting up a new wireless router for a home network. "The virus is streaming in the Indian Internet networks with a high...