Imagine your organization’s digital fortress – now picture a thousand hidden doors, each a potential entry point for cyber threats. In the world of cybersecurity, these doors are known as ‘external attack surface vulnerabilities’ and understanding them is the first step to locking them down.

External attack surface vulnerabilities are the weak points of a company’s network that can potentially be exploited by malicious actors. These include public-facing web servers, email servers, and other services. Companies must be aware of the risks associated with these vulnerable points, and take the appropriate steps to protect their networks from attacks.

In this article, we take a look at the most common external attack surface vulnerabilities, the potential risk they pose to your organization, if exploited, and how to manage these vulnerabilities with an External Attack Surface Management (EASM) solution.

Misconfigured access controls

A survey of 775 cybersecurity experts around the world showed that misconfiguration-related incidents increased by 10% in 2021, a trend that is likely to accelerate further as cloud adoption continues to increase. Even more eye-opening, 27% of organizations pointed to misconfiguration as the main issue facing their organization, far surpassing other concerns like exposed data or compromised accounts.

One recent case really drives home the point. A misconfigured Amazon S3 bucket led to 3TB of airport data—more than 1.5 million files— was left accessible to anyone, with no password required. The files exposed airport worker ID photos and other Personal Identifiable Information (PII), as well as sensitive documents about aircraft and runway maintenance.

Unpatched software and hardware

Unpatched software is another major attack vector for malicious actors. Whether it’s an operating system, web browser, or even a piece of hardware like a router, if it isn’t up-to-date with security patches and updates, attackers may be able to exploit the vulnerabilities.

According to a recent report, more than half of all organizations have at least one device running an operating system or application that is out-of-date. One recent example of the persistent threat in cybersecurity is the targeted attacks on unpatched IBM Aspera Faspex file-exchange software by ransomware groups such as Buhti and IceFire. Although IBM addressed the flaw, designated CVE-2022-47986, active in-the-wild attempts to exploit vulnerable versions continue to be reported, including encryption attacks on multiple servers.

Open ports and services

Open ports can pose serious risks to IT environments, with threat actors exploiting these vulnerabilities through techniques like spoofing, credential sniffing, and other malicious methods.

Several specific ports have been identified as particularly susceptible to cyberattacks, such as ports 20 and 21 (FTP), port 22 (SSH), port 3389 (Remote Desktop), but many others are vulnerable as well.

For example, WannaCry ransomware that exploited SMB vulnerability on, and ongoing campaigns targeting Microsoft’s Remote Desktop Protocol, illustrate the real-world consequences of these vulnerabilities.

Weak network perimeters

A strong network perimeter acts as the first line of defense against external threats. Without proper security measures in place, malicious actors can easily penetrate the network, leading to unauthorized access, data breaches, or even a complete system takeover.

In one of the most sophisticated attacks in recent history, malicious actors compromised the SolarWinds Orion software by inserting a vulnerability into the software’s updates. Weak network perimeters and lack of proper monitoring enabled the attackers to move laterally through the networks of thousands of SolarWinds customers, including several U.S. government agencies.

Phishing and social engineering

The human element still makes up the overwhelming majority of incidents, and is a factor in 74% of total breaches, even as enterprises continue to safeguard critical infrastructure and increase training on cybersecurity protocols.

According to Verizon’s annual Data Breach Investigations Report (DBIR) 2023, social engineering attacks, including Business Email Compromise (BEC) attacks, have proven to be highly effective and profitable avenues for cybercriminals. This might explain why there’s been a substantial increase in these types of attacks, nearly doubling year over year.

Insecure APIs

As organizations continue to rely more on interconnected applications and cloud-based services, the security of APIs has become a focal point in cybersecurity strategies. APIs are a lucrative target for hackers seeking to gain access to personally identifiable information (PII) and orchestrate sophisticated social engineering attacks.

In June 2021, a vulnerability in Twitter’s API was discovered and subsequently patched, but it later led to significant consequences. A hacker claimed to have the personal data of 400 million users for sale on the dark web in December, and the account details and email addresses of 235 million users were released for free. The breach exposed information such as users’ account names, handles, creation dates, follower counts, and email addresses.

Outdated or insecure encryption

Encryption is an essential part of any security strategy. However, outdated or insecure encryption protocols can present major risks.

The recent security incident involving a compromised Microsoft key, attributed to the Chinese threat actor Storm-0558, has wide-reaching implications. Researchers found that the compromised key was not limited to Outlook.com and Exchange Online but could also have been used to forge access tokens for various Azure Active Directory applications, such as SharePoint, Teams, and OneDrive.

While Microsoft mitigated the risk by revoking the affected key, detecting forged tokens may still be challenging for customers due to the lack of logs in the token verification process. The incident underscores the immense power of identity providers’ signing keys and calls for greater security and transparency in protecting such keys to prevent similar future occurrences and reduce their potential impact.

Third-party dependencies

External libraries, offering the advantage of extra functionality without the need to build from scratch, come with the drawback of limited organizational control over their security. This lack of control means that vulnerabilities within these components can jeopardize the entire system.

The danger is especially pronounced with open-source components, as vulnerabilities in them can be exploited by malicious actors with relative ease. Alarmingly, researchers have discovered a 633% increase in cyber-attacks targeting open-source repositories, reflecting the growing risk associated with relying on these external elements.

DDoS attacks

The volume of DDoS attacks targeting financial firms increased 22% year-over-year as of November, according to a new report first provided to Bloomberg. The attackers primarily used application layer attacks, which are difficult to detect and require specialized tools and expertise to successfully mitigate.

Key features and capabilities of EASM solutions

Exploited vulnerabilities can lead to substantial damages including financial losses, reputational damage, and operational disruptions. EASM is a modern approach enabling organizations to gain visibility into their external attack surfaces, identify vulnerabilities, and effectively manage risks. Solutions such as Outpost24 EASM, provide enhanced threat detection, proactive vulnerability management, and improve incident response capabilities.

Here’s an overview of the essential features of an EASM solution and how they contribute to maintaining a resilient cybersecurity posture:

24/7 automated monitoring

• What it does: Continuously monitors the external attack surface for changes and anomalies that might expose vulnerabilities.
• Why you need it: By providing round-the-clock monitoring, it ensures that potential threats are detected early, allowing for swift remediation. This continuous visibility contributes to an organization’s cybersecurity resilience.

Asset discovery

• What it does: Discovers and catalogs all externally facing assets, such as domains, subdomains, IP addresses, and more.
• Why you need it: Knowing all the external assets is the first step in securing them. Asset discovery allows organizations to understand their online presence and therefore make more informed security decisions.

Vulnerability assessment

• What it does: Identifies and prioritizes vulnerabilities across the external attack surface, allowing organizations to understand where they are most at risk.
• Why you need it: By regularly scanning for known vulnerabilities, organizations can patch and secure these weaknesses before they are exploited. This proactive approach enhances the organization’s ability to resist attacks.

Configuration assessment

• What it does: Examines the configuration of externally facing assets to ensure they are aligned with best practices and compliance standards.
• Why you need it: Misconfigurations can often lead to unexpected exposures. By regularly assessing the configuration, organizations can fix these potential vulnerabilities and reduce the attack surface.

Attack surface scoring

• What it does: Provides a quantifiable measure of the security risk of an organization’s external attack surface, often based on various factors like vulnerabilities, configurations, and other risk parameters.
• Why you need it: By having a measurable metric, organizations can track their progress over time and focus their resources on the areas that need the most attention. This contributes to an overall more robust cybersecurity strategy.

Searching for Common Vulnerabilities and Exposures (CVEs)

Common Vulnerabilities and Exposures or CVEs are the most common way to enumerate and name known vulnerabilities. The OWASP Top 10 – “representing a broad consensus about the most critical security risks to web applications”- lists the use of components with known vulnerabilities as number 9. Furthermore, they explain that the impact can be significant: some of the largest breaches to date relied on exploiting vulnerabilities.

Vulnerabilities in your internet-facing assets can:

• Attract attackers: CVEs are more commonly found in old and outdated technologies. This could attract the interest of bad actors as your asset might be less secured than newer more recently introduced assets.
• Be exploitable: The vulnerability might have an existing exploit that could be used to attack the asset, gain access to it or even use it as a pivot point.
• Trigger a service outage: Some vulnerabilities could be triggered by a mix of misconfiguration/coding errors and bad usage leading to crashes and outages in business operations.

Outpost24’s EASM platform maps, monitors and manages your attack surface, including the collection of all technology and host information. This data is obtained by running advanced recon techniques against the scope.

How Outpost24 EASM finds CVEs

The National Institute of Standards and Technology (NIST) maintains the National Vulnerability Database (NVD) which includes every found vulnerability. These vulnerabilities are analyzed using a common framework, defining a severity score (CVSS) from 1 to 10. The EASM Platform is correlating the technology and host information with the NVD to find CVEs present on your internet-facing assets.

Our EASM tool calculates the priority around every CVE observation and notifies you automatically when they appear for your scope. Besides the priority score, each observation contains a specific help text detailing the observation, risk and proposed recommendation.

With auto discovery and proactive monitoring of all your internet-facing assets, you will be the first to know when a vulnerability is found. You can then remediate before a bad actor takes advantage and exploits the CVE. Since our EASM platform automatically sweeps your discovered assets for vulnerabilities, you won’t have to worry about collecting all your assets and manually insert them in a vulnerability scanner.

Best practices for EASM

When implementing and using EASM solutions, organizations should adhere to a set of best practices, including:

• Proactive vulnerability management: Actively seek out weaknesses using tools that offer real-time visibility.
• Regular scanning and monitoring: Continuously scan and monitor for early detection of threats.
• Timely patching: Keep software up-to-date and systematically apply patches to reduce the risk of exploitation.
• Continuous improvement of security controls: Regularly review and update security controls to align with the evolving threat landscape.
• Employee education: Educate staff about common attack methods and foster a culture of cybersecurity mindfulness.

A robust EASM strategy demands a proactive approach, constant vigilance, and an emphasis on education and collaboration. By following these best practices, organizations can build a resilient defense against the ever-changing landscape of cyber threats.

Outpost24’s EASM solution delivers a multi-layered approach to cybersecurity. The synergy of 24/7 monitoring, asset discovery, vulnerability, and configuration assessments, along with attack surface scoring, ensures that organizations are not only aware of their current security posture but also equipped to evolve and adapt to emerging threats.