Bash stuff for fighting a weak DOS attack

100%

Bash stuff for fighting a weak DOS attack

✓ Published0🌍 Public

Last edited Oct 29, 2011

Created on Oct 29, 2011

This example demonstrates a set of bash one-liners for diagnosing and mitigating a weak SYN flood attack on a web server, focusing on analyzing TCP connection states and per-IP connection counts. It shows the sequence of commands used to inspect active port 80 connections via `netstat` and `awk`, increase file descriptor limits with `ulimit`, restart the web server, and identify attacking machines by tallying source IPs. The final step employs `iptables` with the `connlimit` module to reject new connections beyond a threshold, while the code also references `whois` for geolocation. No data visualization libraries are used; the output is purely text-based command-line analysis.

AI-generated description

Similar vizzes

Loading thumbnail…

Gist 7bad13b3f760c4afa2f3

This example shows how to analyze and mitigate a SYN flood attack against a web server, where the attacker opens many TCP connections without sending data. The visualization consists of command-line output and shell scripts, not a graphical chart, and it presents the sequence of diagnostic and defensive steps. The code uses standard Unix tools like `netstat`, `awk`, `sort`, `uniq`, and `cut` to count connections per state and per source IP, as well as `whois` for IP lookup. It also demonstrates `ulimit` to raise the file descriptor limit, `iptables` with the `connlimit` module to cap per-host connections, and the `lighttpd` init script to restart the server. The approach is purely textual, showing the raw commands and their expected outputs.

CCBasis

82% match

Loading thumbnail…

Gist 5383090

This example shows how to forward external HTTP traffic from port 80 to an internal Node.js server listening on port 8000 using iptables NAT rules. The text documents the command-line workflow, including listing the current NAT table, adding a PREROUTING redirect rule, and deleting faulty rules by chain and line number. It also warns against running Node as root for security reasons and acknowledges the risk of disrupting SSH access on port 22. No visualization code or data is present; the example is purely textual documentation of a system administration procedure.

Aalessioalex

56% match

Loading thumbnail…

Gist ebc084e0c56a3c4fbd58

This visualization uses obfuscated PHP code to execute a malicious payload, likely a web shell or backdoor, that performs string manipulation and system commands to compromise a server. The visualization would show the encoded, multi-layered obfuscation process: a long string of percent-encoded, reversed, and base64-like transformations, with nested `preg_replace` and `eval`-style calls that decode and execute hidden instructions. The data shown is the raw source of virus.php, illustrating the complexity of obfuscated malware code rather than a conventional dataset.

WWikunia

53% match

Loading thumbnail…

#localhost

This visualization presents the classic command-line ritual of killing a process occupying a port as an interactive, code-driven narrative. It shows the sequence of running `lsof -i tcp:3000` to identify the process ID and then `kill -9 PID` to terminate it. The code uses the `d3.forceSimulation` API to arrange nodes—each representing a terminal command or system component—into a dynamic, physics-based layout. The rendering relies on the D3.js library for graph structure and layout, with data pulled directly from the provided Gist containing the command sequence. The interaction allows for exploration of the command's textual output.

GGugaGongadze

51% match

Loading thumbnail…

Gist 41f85135dee85195c2a83fc62be90b0a

This example shows a Bash script that installs Firejail and appends a set of filesystem blacklists to the `/etc/firejail/disable-common.local` configuration file. The code uses `apt-get` to update and install the `firejail` package, then checks if the local blacklist file exists before writing entries that deny access to sensitive paths such as `/etc/passwd`, `/etc/nginx`, and `/var/lib/mysql`. The script relies on shell redirection and a here-document to create the configuration content, with no visualization libraries or data sources involved.

IIoTeacher

51% match

Loading thumbnail…

Internet detection via say

This example demonstrates a shell script that continuously monitors network connectivity by pinging a specified host. It shows a real-time alert system where the computer verbally announces when the internet becomes available. The script uses the `ping` command with a one-second timeout and the `say` command to produce an audible "internet alert" message. It operates in an infinite `while` loop, checking every second. The concrete APIs involved are the standard Unix utilities `ping` and `say`, with no graphical or data-visualization libraries present.

Aadkatrit

50% match

Loading thumbnail…

Turn off the firewall on a Linux machine

This example illustrates the sequence of commands for disabling a firewall on a Linux machine, visually organized as a static flowchart. The visualization maps each shell command (such as `sudo service iptables stop` and `sudo ufw off`) into distinct nodes, with arrows indicating the logical order of execution. The code relies on the D3.js library’s `d3.hierarchy` and `d3.tree` APIs to compute the layout, while `d3.select` and `d3.enter` render the SVG elements. The data source is the author’s own gist, manually parsed into a hierarchical JSON structure for the tree diagram.

PP7h

50% match

Loading thumbnail…

Gist 8368366d8665351503d6

This example demonstrates PHP snippets for handling MySQL database operations in a web application, focusing on user IP tracking and survey response counting. It shows duplicate IP checks using `$_SERVER["REMOTE_ADDR"]` combined with `SELECT COUNT(*)` queries, followed by prepared statements for single and multiple row inserts via `$db->prepare()` and `bindValue()`. The code also counts total responses by selecting `COUNT(*)` from a table, and tallies specific answer values through `WHERE` clauses with `rowCount()`. No visualization libraries or rendering techniques appear; the example relies purely on server-side SQL logic.

LLayne Smith

50% match