In the third quarter, attackers continued to exploit security flaws in WinRAR, while the total number of registered vulnerabilities grew again. In this report, we examine statistics on published vulnerabilities and exploits, the most common security issues impacting Windows and Linux, and the vulnerabilities being leveraged in APT attacks that lead to the launch of widespread C2 frameworks. The report utilizes anonymized Kaspersky Security Network data, which was consensually provided by our users, as well as information from open sources.
Statistics on registered vulnerabilities
This section contains statistics on registered vulnerabilities. The data is taken from cve.org.
Let us consider the number of registered CVEs by month for the last five years up to and including the third quarter of 2025.
Total published vulnerabilities by month from 2021 through 2025 (download)
As can be seen from the chart, the monthly number of vulnerabilities published in the third quarter of 2025 remains above the figures recorded in previous years. The three-month total saw over 1000 more published vulnerabilities year over year. The end of the quarter sets a rising trend in the number of registered CVEs, and we anticipate this growth to continue into the fourth quarter. Still, the overall number of published vulnerabilities is likely to drop slightly relative to the September figure by year-end
A look at the monthly distribution of vulnerabilities rated as critical upon registration (CVSS > 8.9) suggests that this metric was marginally lower in the third quarter than the 2024 figure.
Total number of critical vulnerabilities published each month from 2021 to 2025 (download)
Exploitation statistics
This section contains exploitation statistics for Q3 2025. The data draws on open sources and our telemetry.
Windows and Linux vulnerability exploitation
In Q3 2025, as before, the most common exploits targeted vulnerable Microsoft Office products.
Most Windows exploits detected by Kaspersky solutions targeted the following vulnerabilities:
- CVE-2018-0802: a remote code execution vulnerability in the Equation Editor component
- CVE-2017-11882: another remote code execution vulnerability, also affecting Equation Editor
- CVE-2017-0199: a vulnerability in Microsoft Office and WordPad that allows an attacker to assume control of the system
These vulnerabilities historically have been exploited by threat actors more frequently than others, as discussed in previous reports. In the third quarter, we also observed threat actors actively exploiting Directory Traversal vulnerabilities that arise during archive unpacking in WinRAR. While the originally published exploits for these vulnerabilities are not applicable in the wild, attackers have adapted them for their needs.
- CVE-2023-38831: a vulnerability in WinRAR that involves improper handling of objects within archive contents We discussed this vulnerability in detail in a 2024 report.
- CVE-2025-6218 (ZDI-CAN-27198): a vulnerability that enables an attacker to specify a relative path and extract files into an arbitrary directory. A malicious actor can extract the archive into a system application or startup directory to execute malicious code. For a more detailed analysis of the vulnerability, see our Q2 2025 report.
- CVE-2025-8088: a zero-day vulnerability similar to CVE-2025-6128, discovered during an analysis of APT attacks The attackers used NTFS Streams to circumvent controls on the directory into which files were unpacked. We will take a closer look at this vulnerability below.
It should be pointed out that vulnerabilities discovered in 2025 are rapidly catching up in popularity to those found in 2023.
All the CVEs mentioned can be exploited to gain initial access to vulnerable systems. We recommend promptly installing updates for the relevant software.
Dynamics of the number of Windows users encountering exploits, Q1 2023 — Q3 2025. The number of users who encountered exploits in Q1 2023 is taken as 100% (download)
According to our telemetry, the number of Windows users who encountered exploits increased in the third quarter compared to the previous reporting period. However, this figure is lower than that of Q3 2024.
For Linux devices, exploits for the following OS kernel vulnerabilities were detected most frequently:
- CVE-2022-0847, also known as Dirty Pipe: a vulnerability that allows privilege escalation and enables attackers to take control of running applications
- CVE-2019-13272: a vulnerability caused by improper handling of privilege inheritance, which can be exploited to achieve privilege escalation
- CVE-2021-22555: a heap overflow vulnerability in the Netfilter kernel subsystem. The widespread exploitation of this vulnerability is due to its use of popular memory modification techniques: manipulating “msg_msg” primitives, which leads to a Use-After-Free security flaw.
Dynamics of the number of Linux users encountering exploits, Q1 2023 — Q3 2025. The number of users who encountered exploits in Q1 2023 is taken as 100% (download)
A look at the number of users who encountered exploits suggests that it continues to grow, and in Q3 2025, it already exceeds the Q1 2023 figure by more than six times.
It is critically important to install security patches for the Linux operating system, as it is attracting more and more attention from threat actors each year – primarily due to the growing number of user devices running Linux.
Most common published exploits
In Q3 2025, exploits targeting operating system vulnerabilities continue to predominate over those targeting other software types that we track as part of our monitoring of public research, news, and PoCs. That said, the share of browser exploits significantly increased in the third quarter, matching the share of exploits in other software not part of the operating system.
Distribution of published exploits by platform, Q1 2025 (download)
Distribution of published exploits by platform, Q2 2025 (download)
Distribution of published exploits by platform, Q3 2025 (download)
It is noteworthy that no new public exploits for Microsoft Office products appeared in Q3 2025, just as none did in Q2. However, PoCs for vulnerabilities in Microsoft SharePoint were disclosed. Since these same vulnerabilities also affect OS components, we categorized them under operating system vulnerabilities.
Vulnerability exploitation in APT attacks
We analyzed data on vulnerabilities that were exploited in APT attacks during Q3 2025. The following rankings draw on our telemetry, research, and open-source data.
TOP 10 vulnerabilities exploited in APT attacks, Q3 2025 (download)
APT attacks in Q3 2025 were dominated by zero-day vulnerabilities, which were uncovered during investigations of isolated incidents. A large wave of exploitation followed their public disclosure. Judging by the list of software containing these vulnerabilities, we are witnessing the emergence of a new go-to toolkit for gaining initial access into infrastructure and executing code both on edge devices and within operating systems. It bears mentioning that long-standing vulnerabilities, such as CVE-2017-11882, allow for the use of various data formats and exploit obfuscation to bypass detection. By contrast, most new vulnerabilities require a specific input data format, which facilitates exploit detection and enables more precise tracking of their use in protected infrastructures. Nevertheless, the risk of exploitation remains quite high, so we strongly recommend applying updates already released by vendors.
C2 frameworks
In this section, we will look at the most popular C2 frameworks used by threat actors and analyze the vulnerabilities whose exploits interacted with C2 agents in APT attacks.
The chart below shows the frequency of known C2 framework usage in attacks on users during the third quarter of 2025, according to open sources.
Top 10 C2 frameworks used by APT groups to compromise user systems in Q3 2025 (download)
Metasploit, whose share increased compared to Q2, tops the list of the most prevalent C2 frameworks from the past quarter. It is followed by Sliver and Mythic. The Empire framework also reappeared on the list after being inactive in the previous reporting period. What stands out is that Adaptix C2, although fairly new, was almost immediately embraced by attackers in real-world scenarios. Analyzed sources and samples of malicious C2 agents revealed that the following vulnerabilities were used to launch them and subsequently move within the victim’s network:
- CVE-2020-1472, also known as ZeroLogon, allows for compromising a vulnerable operating system and executing commands as a privileged user.
- CVE-2021-34527, also known as PrintNightmare, exploits flaws in the Windows print spooler subsystem, also enabling remote access to a vulnerable OS and high-privilege command execution.
- CVE-2025-6218 or CVE-2025-8088 are similar Directory Traversal vulnerabilities that allow extracting files from an archive to a predefined path without the archiving utility notifying the user. The first was discovered by researchers but subsequently weaponized by attackers. The second is a zero-day vulnerability.
Interesting vulnerabilities
This section highlights the most noteworthy vulnerabilities that were publicly disclosed in Q3 2025 and have a publicly available description.
ToolShell (CVE-2025-49704 and CVE-2025-49706, CVE-2025-53770 and CVE-2025-53771): insecure deserialization and an authentication bypass
ToolShell refers to a set of vulnerabilities in Microsoft SharePoint that allow attackers to bypass authentication and gain full control over the server.
- CVE-2025-49704 involves insecure deserialization of untrusted data, enabling attackers to execute malicious code on a vulnerable server.
- CVE-2025-49706 allows access to the server by bypassing authentication.
- CVE-2025-53770 is a patch bypass for CVE-2025-49704.
- CVE-2025-53771 is a patch bypass for CVE-2025-49706.
These vulnerabilities form one of threat actors’ combinations of choice, as they allow for compromising accessible SharePoint servers with just a few requests. Importantly, they were all patched back in July, which further underscores the importance of promptly installing critical patches. A detailed description of the ToolShell vulnerabilities can be found in our blog.
CVE-2025-8088: a directory traversal vulnerability in WinRAR
CVE-2025-8088 is very similar to CVE-2025-6218, which we discussed in our previous report. In both cases, attackers use relative paths to trick WinRAR into extracting archive contents into system directories. This version of the vulnerability differs only in that the attacker exploits Alternate Data Streams (ADS) and can use environment variables in the extraction path.
CVE-2025-41244: a privilege escalation vulnerability in VMware Aria Operations and VMware Tools
Details about this vulnerability were presented by researchers who claim it was used in real-world attacks in 2024.
At the core of the vulnerability lies the fact that an attacker can substitute the command used to launch the Service Discovery component of the VMware Aria tooling or the VMware Tools utility suite. This leads to the unprivileged attacker gaining unlimited privileges on the virtual machine. The vulnerability stems from an incorrect regular expression within the get-versions.sh script in the Service Discovery component, which is responsible for identifying the service version and runs every time a new command is passed.
Conclusion and advice
The number of recorded vulnerabilities continued to rise in Q3 2025, with some being almost immediately weaponized by attackers. The trend is likely to continue in the future.
The most common exploits for Windows are primarily used for initial system access. Furthermore, it is at this stage that APT groups are actively exploiting new vulnerabilities. To hinder attackers’ access to infrastructure, organizations should regularly audit systems for vulnerabilities and apply patches in a timely manner. These measures can be simplified and automated with Kaspersky Systems Management. Kaspersky Symphony can provide comprehensive and flexible protection against cyberattacks of any complexity.