Flawfinder – Source Code Auditing Tool


Flawfinder is a source code auditing tool that reports possible security weaknesses (flaws) sorted by risk level. It’s very useful for quickly finding and removing at least some potential security problems before a program is widely released to the public. It’s a static analysis source code auditing tool.

Flawfinder - Source Code Auditing Tool


Using Flawfinder Source Code Auditing Tool

It is specifically designed to be easy to install and use. After installing it, at a command line just type:

Also it works on Unix-like systems today (it’s been tested on GNU/Linux), and it should be easy to port to Windows systems. It requires Python 1.5 or greater to run (Python 1.3 or earlier won’t work).

Flawfinder Speed

Flawfinder is written in Python, to simplify the task of writing and extending it. Python code is not as fast as C code, but for the task I believe it’s just fine. The earlier version 0.12 on a 400Mhz Pentium II system analyzed 51055 lines in 39.7 seconds, resulting in an average of 1285 analyzed lines/second. Flawfinder 1.20 and later will report their speed (in analyzed lines/second) if you’re curious.

How Flawfinder works


Flawfinder works by using a built-in database of C/C++ functions with well-known problems, such as buffer overflow risks (e.g., strcpy(), strcat(), gets(), sprintf(), and the scanf() family), format string problems ([v][f]printf(), [v]snprintf(), and syslog()), race conditions (such as access(), chown(), chgrp(), chmod(), tmpfile(), tmpnam(), tempnam(), and mktemp()), potential shell metacharacter dangers (most of the exec() family, system(), popen()), and poor random number acquisition (such as random()). The good thing is that you don’t have to create this database – it comes with the tool.

It then takes the source code text, and matches the source code text against those names, while ignoring text inside comments and strings (except for directives). It also knows about gettext (a common library for internationalized programs), and will treat constant strings passed through gettext as though they were constant strings; this reduces the number of false hits in internationalized programs.

You can download Flawfinder here:

flawfinder-2.0.4.tar.gz

Or read more here.

Posted in: Secure Coding, Security Software

, , , ,


Latest Posts:


OWASP APICheck - HTTP API DevSecOps Toolset OWASP APICheck – HTTP API DevSecOps Toolset
APICheck is an HTTP API DevSecOps toolset, it integrates existing tools, creates execution chains easily and is designed for integration with 3rd parties.
trident - Automated Password Spraying Tool trident – Automated Password Spraying Tool
The Trident project is an automated password spraying tool developed to be deployed on multiple cloud providers and provides advanced options around scheduling
tko-subs - Detect & Takeover Subdomains With Dead DNS Records tko-subs – Detect & Takeover Subdomains With Dead DNS Records
tko-subs is a tool that helps you to detect & takeover subdomains with dead DNS records, this could be dangling CNAMEs point to hosting services and more.
Arcane - Tool To Backdoor iOS Packages (iPhone ARM) Arcane – Tool To Backdoor iOS Packages (iPhone ARM)
Arcane is a simple script tool to backdoor iOS packages (iPhone ARM) and create the necessary resources for APT repositories.
SharpHose - Asynchronous Password Spraying Tool SharpHose – Asynchronous Password Spraying Tool
SharpHose is an asynchronous password spraying tool in C# for Windows environments that takes into consideration fine-grained password policies and can be run over Cobalt Strike's execute-assembly.
Axiom - Pen-Testing Server For Collecting Bug Bounties Axiom – Pen-Testing Server For Collecting Bug Bounties
Project Axiom is a set of utilities for managing a small dynamic infrastructure setup for bug bounty, basically a pen-testing server out of the box with 1-line.


3 Responses to Flawfinder – Source Code Auditing Tool

  1. d3m4s1@d0v1v0 September 16, 2009 at 7:00 pm #

    Another interesting tool to put in the bag.
    Finding potential buffer overflows before the program gets into production is a very critical task, it’s a shame that the programmers not always are aware of this…

  2. Andrew September 16, 2009 at 7:17 pm #

    What language(s) does it scan? Can I throw any source files at it, or is it just for C/C++?

  3. Jannich Brendle September 17, 2009 at 2:21 am #

    Andrew: Yes, flawfinder will only find flaws in C and C++ at the moment.