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Recent May-July 2022 observations of network security trends and exploits used in the wild reveal that attackers have been making use of newly published remote code execution vulnerabilities. In our observations of network security trends, Unit 42 researchers have pinpointed several attacks based on proof-of-concept (PoC) availability and impact. We have detailed below which of these we believe should be on the defender’s radar.
Other insights that could assist defenders include the following:
- Rankings of the most commonly used attack techniques and the types of vulnerabilities that attackers have recently favored. For example, among 5,976 newly published vulnerabilities, a large portion (almost 11.6%) involves cross-site-scripting.
- Lists of major vulnerabilities identified by evaluating more than 340 million attack sessions including remote code execution, directory traversal and information disclosure.
- Insight into how these vulnerabilities are exploited in the wild based on real-world data collected from our Next-Generation Firewalls.
- Summaries of key trends from May-July 2022.
- Analysis of the most recently published vulnerabilities, including the severity and attack origin distribution.
- Classification of these vulnerabilities to provide a clear view of the prevalence of the different types, such as cross-site scripting or denial-of-service.
- Lists of the most commonly exploited vulnerabilities attackers are using, as well as the severity, category and origin of each attack.
Palo Alto Networks customers receive protections from the vulnerabilities discussed here through the Next-Generation Firewall and Cloud-Delivered Security Services, including Threat Prevention, WildFire, Advanced URL Filtering and Cortex XDR.
|Types of Attacks and Vulnerabilities Covered||Cross-site scripting, denial of service, information disclosure, buffer overflow, privilege escalation, memory corruption, code execution, SQL injection, out-of-bounds read, cross-site request forgery, directory traversal, command injection, improper authentication, security feature bypass|
|Related Unit 42 Topics||Network Security Trends, exploits in the wild, attack analysis|
- Analysis of Published Vulnerabilities, May-July 2022
- Network Security Trends: Analysis of Exploits in the Wild, May-July 2022
- Exploits in the Wild, May-July 2022: A Detailed View of Network Security Trends
- Additional Resources
From May-July 2022, a total of 5,976 new Common Vulnerabilities and Exposures (CVE) numbers were registered. To better understand the potential impact these newly published vulnerabilities could have on network security, we provide our observations based on the severity, availability of working proof-of-concept (PoC) code, and vulnerability categories.
To estimate the potential impact of vulnerabilities, we consider their severity and examine any reliable PoCs available that attackers could easily launch. Some of the public sources we use to find PoCs are Exploit-DB, GitHub and Metasploit. Distribution of the 5,976 CVEs that have an assigned severity score of medium or higher can be seen in the following table:
Table 1. Severity distribution for CVEs registered May-July 2022, including only those rated medium-critical.
Our classification of vulnerabilities is based on CVSS v3 scores. Many conditions must be met to rate a vulnerability as critical, so there are very few at this level. One of the common factors for rating a vulnerability at this level is having a working PoC available. To be considered critical, vulnerabilities generally have low attack complexity, and it is often easy to create a PoC to exploit them.
In the period discussed, the critical-severity ratios increased while high-severity and medium-severity PoC ratios decreased slightly.
It is crucial to understand each type of vulnerability and its consequences. Out of the newly published CVEs that were analyzed, 23.5% are classified as local vulnerabilities, requiring prior access to compromised systems, while the remaining 76.5% are remote vulnerabilities, which can be exploited over a network. This means that most newly published vulnerabilities introduce potential opportunities for threat actors to attack vulnerable organizations from anywhere in the world.
In Figure 2, the most common vulnerability types are ranked by how prevalent they were among the most recent set of published vulnerabilities.
Cross-site scripting remains the most reported vulnerability during May-July 2022. We also saw that the prevalence of SQL injection vulnerabilities increased during this time, and many of the vulnerabilities in this category are ranked critical. The number of SQL injection and cross-site scripting vulnerabilities slightly increased and out-of-bound vulnerabilities decreased. Most of the recently published cross-site scripting and information disclosure attacks are usually at medium or high severity (rather than critical).
By leveraging Palo Alto Networks Next-Generation Firewalls as sensors on the perimeter, Unit 42 researchers observed malicious activities from May-July 2022. The malicious traffic we identified is further processed and based on metrics such as IP addresses, port numbers and timestamps. This ensures the uniqueness of each attack session and thus eliminates potential data skews. We analyzed 340 million valid malicious sessions and then correlated the refined data with other attributes to infer attack trends over time to get a picture of the threat landscape.
To arrive at 340 million valid malicious sessions, we excluded the original set of low-severity signature triggers used to detect scanning and brute-force attacks, as well as internal triggers used for research purposes. Therefore, we consider exploitable vulnerabilities with a medium and higher severity ranking (based on the CVSS v3 Score) as a verified attack.
Figure 4 shows the ratio of attacks grouped by the severity of each vulnerability. Compared with the previous quarters' severity distribution, this quarter shows a decrease in critical- and high-severity attacks and an increase in medium-severity attacks. However, we still focus more on critical-severity attacks because of their greater potential impact. Many published vulnerabilities are scored medium severity, but attackers typically leverage more severe vulnerabilities for exploits. Defenders should prioritize preventing and mitigating high- and critical-severity network attacks.
During May-July 2022, attackers gradually increased their exploitation of vulnerabilities of medium severity, and the number of attacks gradually increased (the last set of data records eight days of attack volume instead of seven days).
As we’ve seen in the past, attackers frequently use recently disclosed vulnerabilities, especially those from 2021-22. This shows the importance of updating security products and applying software patches as soon as they become available to protect against the most recently discovered vulnerabilities.
We classified each network attack by category and organized them in terms of prevalence. In the period discussed, remote code execution ranks first, followed by information disclosure. Attackers typically want to gain as much information and control as possible over the systems they target. Traversal attacks decreased this quarter.
After identifying the region from which each network attack originated, we discovered that the majority of them seem to originate from the United States, followed by Germany then the Netherlands. Attacks from the Netherlands and Romania increased significantly this quarter. However, we recognize that the attackers might leverage proxy servers and VPNs located in those countries to hide their actual physical locations.
The vulnerabilities disclosed from May-July 2022 indicate that web applications remain popular targets for attackers, and that critical vulnerabilities are more likely to have PoCs publicly available.
In the meantime, we continue to capture newly published vulnerabilities that are exploited in the wild. This emphasizes the need for organizations to promptly patch their systems and implement security best practices. Attackers continue to make a concerted effort to expand their tool kit of exploits whenever possible.
While cybercriminals will never cease their malicious activities, Palo Alto Networks customers receive protections from the attacks discussed in this blog through the Next-Generation Firewall and Cloud-Delivered Security Services, including Threat Prevention, WildFire and Advanced URL Filtering, as well as through Cortex XDR.
To further mitigate any risks to your network:
- Run a Best Practice Assessment to identify where your configuration could be altered to improve your security posture.
- Run a Security Lifecycle Review to get a consolidated view of your largest threats and if you have coverage to prevent them.
- Continuously update your Next-Generation Firewalls with the latest Palo Alto Networks Threat Prevention content (e.g. versions 8638 and above).