Because of crackers, modern data centers employ firewalls and managed networking components, but they still feel uneasy about their security. As a result, there is an urgent need for tools that can accurately assess the vulnerability of networks. This article presents the top ten assessment tools for dealing with these issues, which have been categorized based on their popularity, functionality, and ease of use, among other factors.
Every software and hardware system contains vulnerabilities, which are unfortunately an unavoidable part of the process. The presence of a bug in the operating system, a security flaw in a commercial product, or the incorrect configuration of critical infrastructure components makes systems vulnerable to cyber-attacks. Malicious IT professionals can exploit these flaws to gain access to systems and steal information for personal or commercial gain. While this is not an easy task in terms of technical difficulty, there have been enough successful attempts to warrant concern.
Previously, it was assumed that this was only true for commercial products. However, open-source systems have recently been compromised, resulting in data theft as well as a loss of reputation or financial resources. Websites, in addition to local area networks, are vulnerable and have become a popular target for crackers in recent years. In a nutshell, vulnerabilities can be exploited both internally within an organization and externally via the Internet by unknown individuals.
On the plus side, as the number of attacks continues to rise, there are an increasing number of tools available to detect and prevent malware and cracking attempts. There are a plethora of such utilities available in the open-source community (and distros). The BackTrack Linux distribution, which has gained international renown for its comprehensive suite of vulnerability assessment and digital forensics software utilities, deserves special mention. The most recent version also includes powerful wireless vulnerability testing tools, which are described below.
Although there are hundreds of tools available, I have chosen the top 10 based on the fact that no other tool can truly replace them. Features, product popularity among security professionals, and ease of use have all been important considerations in the selection process, according to our experts.
Please refer to Figure 1, which depicts the top five network assessment tools I selected, and Figure 2, which depicts the leading Web vulnerability scanning products. Of course, only free and open-source software (FOSS) tools are mentioned. I’ve organized the tools in the order in which they are expected to be used to detect vulnerabilities; this should provide readers who wish to pursue a career as certified penetration testers with a systematic approach to identifying vulnerabilities.
The top 5 network security assessment tools
Network vulnerability scanning must be carried out from both within and outside the network (from both “sides” of the firewall) to be effective. Start with the network evaluation phase, where sniffing and primary attacks are carried out, as this is the approach that I would recommend starting with. The information gathered during the collection phase is used during the attack phase to exploit the vulnerabilities that have been exposed.
The very first step in conducting a vulnerability assessment is to get a clear picture of what is going on in the network itself. Wireshark (previously known as Ethereal) operates in promiscuous mode, allowing it to capture all traffic within a TCP broadcast domain (see Figure 1).
Customized filters can be configured to intercept specific types of traffic; for example, they can be configured to capture the communication between two IP addresses or to capture UDP-based DNS queries on the network, for example. Traffic data can be captured and saved in a capture file, which can then be reviewed at a later time. During the review process, additional filters can be applied.
For the most part, the tester is looking for errant IP addresses, spoofed packets, unnecessary packet drops, and suspicious packet generation from a single IP address. Wireshark provides a comprehensive and clear picture of what is taking place on a network.
It does not, however, possess any intelligence of its own and should only be used as a data provider. Because of its user-friendly graphical user interface, it is accessible to anyone with even rudimentary computer skills.
This is most likely the only tool that has maintained its popularity for nearly a decade. In addition to crafting packets, this scanner is capable of performing scans at the TCP level of granularity, such as SYN scan, ACK scan, and so on. It has built-in signature-checking algorithms that can be used to guess the operating system and version from network responses such as a TCP handshake, for example.
Nmap is capable of detecting remote devices and, in the majority of cases, correctly identifies firewalls, routers, and the manufacturer and model of the device. NetAdmins can use Nmap to determine which ports are open on their networks, as well as whether or not those ports can be exploited further in simulated attacks. In plain text and with lots of detail, the output can be scripted to automate routine tasks and to gather evidence for an audit report, among other applications.
For a better understanding of Nmap, you can refer to the series of Nmap articles that were previously published.
Once the sniffing and scanning have been completed using the tools listed above, it is time to move on to the operating system and application level. A fantastic and powerful open-source framework for performing rigorous scans against a list of IP addresses, Metasploit is available for free download.
Unlike many other frameworks, it has the additional capability of being used for anti-forensics. Programmers with extensive experience can write a piece of code that exploits a specific vulnerability and then test it with Metasploit to see if it is detected. Technically, this process can be reversed: when a virus attacks using an unknown vulnerability, the tool Metasploit can be used to test the patch for that vulnerability.
Although this is a commercial tool, I have included it because the community edition is completely free and does not make any compromises on the feature set.
In the commercial world, the Nessus scanner is well-known, and it is from this utility that OpenVAS branched out a few years ago to remain open source. Although Metasploit and OpenVAS are very similar, there is a significant difference between them.
Essentially, OpenVAS is composed of two major components: a scanner and a manager. A scanner may be installed on the target to be scanned and communicate the results of the vulnerability scan to the manager. When generating a report, the manager gathers inputs from multiple scanners and applies its intelligence to the data.
In the security community, OpenVAS is regarded as extremely stable and dependable when it comes to detecting the most recent security flaws and providing reports and inputs to help close them down. A built-in Greenbone security assistant provides a graphical user interface (GUI) dashboard that lists all vulnerabilities as well as the machines that have been impacted on the network.
One of the features that make OpenVAS a popular tool among infrastructure security managers is the ability to generate detailed reports.
Except for wireless security scanners, the list of network scanners would be incomplete. Wireless devices are now included in today’s infrastructure, both in the data center and in corporate offices, to better serve mobile users. While having WPA-2 security is considered adequate for 802.11 WLAN standards, misconfiguration and the use of overly simple passwords leave such networks vulnerable to attack, according to the authors.
Aircrack is a collection of software utilities that performs functions such as sniffing, packet crafting, and packet decoding. A targeted wireless network is subjected to packet traffic to obtain critical information about the underlying encryption system. After that, a decryptor is used to brute-force the captured file to discover passwords. Aircrack is capable of running on the majority of Linux distributions, but the version included with BackTrack Linux is highly recommended.
The top five Web security assessment tools
When compared to network scans, scanning websites is a completely different ballgame. In the case of websites, the scope of the scan ranges from Layer 2 to Layer 7, depending on the intrusiveness of the most recently discovered vulnerabilities. Starting with web-level access and progressing through all backend components such as databases, the correct approach for scanning websites should be taken. Although the majority of Web security scanners are automated, depending on the situation, manual scripting may be required.
We’ll start with this tool because of the variety of features it offers. In addition to supporting HTTP and HTTPS, this open-source tool also provides findings in an interactive format that makes it a popular website scanning tool. Nikto is capable of crawling a website in the same manner as a human would, and he does so in the shortest amount of time. It employs a technique known as a mutation, in which it creates combinations of various HTTP tests that are combined to form an attack, which is based on the Web server configuration and the code that is hosted on the server.
As a result, it detects critical flaws such as incorrect file upload configuration, incorrect cookie handling, cross-scripting errors, and so on. When Nikto runs in verbose mode, it dumps all of its findings, which allows you to learn more about Web vulnerabilities in greater detail. The downside is that a large number of things may be alerted at the same time, with some of them being false alarms. As a result, caution should be exercised when interpreting Nikto logs.
The “deep-dive” approach is taken after Nikto has completed a baseline check to determine the next step. Samurai is a framework comprised of a collection of powerful utilities, each of which is designed to exploit a specific set of vulnerabilities.
A Linux distribution is solely focused on penetration-testing tools such as WebScarab for HTTP mapping, W3AF plugins for application-based attacks, and tools to test browser-based exploits. It is available as a free download. That the most recent version can detect vulnerabilities that are typically not detected by even a few commercial software products is remarkable to note.
However, while the first two tools are adequate for static websites, we require something that can deal with HTTP sessions and cookies to create portals that require a username and password. Safe3 scanner is a fantastic open-source project that has gained popularity and momentum as a result of its ability to handle almost all types of authentication, including NTLM authentication.
Despite being very similar to Samurai, Websecurify also includes application-level assessment as a component of its functionality. The application of standards in a large Web farm where code is maintained by a team of developers may result in insecure code such as passwords mentioned in code, physical file paths in libraries, and so on. Web security is capable of quickly traversing code and identifying such loopholes.
One useful feature is that it allows you to create screenshots of problem areas on the fly, which is useful when preparing audit reports and other documentation. It is one of the very few platform-independent tools on the market, and it also supports mobile coding, which is helping it to become more popular in the world of cyber-security evaluation.
This article would be incomplete if I did not mention a tool that can be used to detect SQL injection attacks. Even though this is a very old “first-generation” type of attack, many publicly accessible websites are still unable to prevent it. SQLmap is capable of not only exploiting SQL-injection errors, but it is also capable of taking control of the database server itself. Because it is focused on a specific task, it can work at high speeds to fingerprint databases, determine the underlying file system and operating system, and eventually fetch data from the server. It has been designed to work with almost all well-known database engines and is also capable of performing password guessing attacks. This tool, in conjunction with the other four tools mentioned above, can be used to scan a website aggressively.
In addition to network scanning, a vulnerability assessment tool should include website vulnerability exploitation as well as vulnerability exploitation on third-party websites. Open-source software is also vulnerable to attacks; as a result, network administrators must be familiar with reputable scanners and incorporate them into their daily routines to keep their infrastructure secure and stable.