
Arctic Wolf Presents
The Most Exploited Vulnerabilities of 2023
YoY Vulnerability CVSS v3 Severity Breakdown
* For CVEs published in the last 10 years
More troubling than the sheer volume of vulnerabilities in 2023 is that over half of them were given a CVSS score indicating high or critical severity — an increase of 57% YoY. Exploiting these vulnerabilities proved lucrative for threat actors around the world and wrought significant reputational, financial, and operational damage on the organizations they attacked. As organizations establish their cybersecurity priorities for 2024, it’s vital they look back at how vulnerabilities became data breaches in 2023.

A look at the Top 30 Vulnerabilities
In our list of the 30 most exploited vulnerabilities of the year, you'll uncover trends and insights you can use to guide your remediation and vulnerability management plans in the new year. You’ll also discover the fundamentals too many organizations are missing and learn how to leverage them to reinforce your cybersecurity foundation and amplify your resilience.
Vulnerability Name
CVE-2023-34362
"The MOVEit Transfer vulnerability" - Exploited by the Cl0p ransomware group. Several high profile companies were listed on their leak site.
CVE-2023-34362 At A Glance
A critical zero-day privilege escalation vulnerability disclosed in May 2023 within MOVEit Transfer, a managed file transfer (MFT). The exploitation of this vulnerability could lead to escalated privileges and potential unauthorized access to an environment. The Cl0p ransomware group exploited this vulnerability to steal information from over 2,000 companies, including several high profile entites. In these attacks, Cl0p aimed to extract information and then coerced the targeted organizations into contacting them for ransom payment, threatening to expose their data if the payment was not made.
Vulnerability Name
CVE-2023-4966
"Citrix bleed" - Exploited by LockBit 3.0 affiliates and nation-state threat actors.
CVE-2023-4966 At A Glance
An information disclosure vulnerability in Citrix NetScaler ADC and Netscaler Gateway that was exploited by nation-state threat actors and LockBit 3.0 affiliates. The vulnerability, dubbed "Citrix Bleed", allows an unauthenticated remote threat actor to access memory outside the intended buffer boundaries when certain operations are performed on a memory buffer. LockBit 3.0 affiliates leveraged Citrix Bleed to target Boeing and Industrial and Commerical Bank of China (ICBC) in late 2023. Although NIST NVD rated this vulnerability as a high severity, Citrix labeled this as a critical vulnerability at a CVSS of 9.4.
Vulnerability Name
CVE-2023-20198
A maximum severity privilege escalation vulnerability. Over 40,000 Cisco Devices were discovered to be compromised.
CVE-2023-20198 At A Glance
In October 2023, Cisco disclosed an actively exploited critical privilege escalation vulnerability in the Web UI feature of the Cisco IOS XE operating system. The vulnerability could allow a remote, unauthenticated threat actor to create an account with maximum privileges (privilege level 15 access) on the affected device. At the time, this vulnerability did not have an official patch and Cisco provided workarounds as a temporary fix to prevent exploitation. A total of over 40,000 Cisco devices running the IOS XE operating system fell victim to compromise.
Vulnerability Name
CVE-2023-22518
A critical improper authorization vulnerability that was used to deploy Cerber ransomware.
CVE-2023-22518 At A Glance
A critical improper authorization vulnerability that allows a remote unauthenticated threat actor to reset confluence and create a Confluence instance administrator account. At the time, however, Atlassian stated that this vulnerability could only cause data loss and threat actors could not exfiltrate data. Subsequently, in November 2023, this vulnerability was observed being exploited in the wild to deploy Cerber ransomware and Atlassian updated the vulnerability's details.
Vulnerability Name
CVE-2023-2868
Replace your compromised ESG appliances - UNC4841 exploited this vulnerability to perform espionage. Initial patches by Barracuda were ineffective.
CVE-2023-2868 At A Glance
A critical remote code execution (RCE) vulnerability in Barracuda ESG appliances. Barracuda ESG is an email security gateway that manages and filters inbound/outbound traffic within an organization's network. This vulnerability existed in the module that initially screens the attachments of incoming emails, and was exploited by the China-nexus threat actor UNC4841 for espionage. Originally when Barracuda published their advisory, they stated that all affected appliances receved a patch. However shortly after, it was determined the patch was ineffective and impacted customers had to replace their ESG appliances.
Vulnerability Name
CVE-2023-20269
Information disclosure vulnerability exploited by the LockBit and Akira ransomware groups to target organizations across a variety of industries.
CVE-2023-20269 At A Glance
In September 2023, Cisco revealed a zero-day vulnerability in the remote access VPN feature of Cisco ASA and Cisco Firepower Threat Defense (FTD) Software. This vulnerability enables threat actors to make unlimited attempts with username/password combinations, attributed to the inadequate separation of authentication, authorization, and accounting (AAA). The Akira and LockBit ransomware groups widely exploited this vulnerability to target organizations across a variety of industries. Shortly before this vulnerability was officially disclosed, Arctic Wolf observed an Akira ransomware campaign targeting Cisco ASA VPN appliances (https://arcticwolf.com/resources/blog/ongoing-ransomware-campaign-against-cisco-asa-vpn-appliances/). Although this vulnerability is rated as a critical severity by NIST NVD, Cisco labeled it as a medium severity vulnerability with a CVSS score of 5.0.
Vulnerability Name
CVE-2023-27350
Bl00dy - This vulnerability was exploited by Bl00dy, Cl0p and Lockbit.
CVE-2023-27350 At A Glance
In April 2023, Papercut disclosed that threat actors are exploiting CVE-2023-27350 to target print management servers. The vulnerability allows unauthenticated threat actors to bypass authentication and execute arbritrary code in the context of SYSTEM on a PaperCut Application Server. This vulnerability was exploited by a variety of threat actors including ransomware groups such as Bl00dy, Cl0p and Lockbit.
Vulnerability Name
CVE-2023-22515
Broken access control flaw that allowed threat actors to become Confluence administrators.
CVE-2023-22515 At A Glance
A critical vulnerability arose from a broken access control flaw in Confluence Data Center and Server. This flaw enabled threat actors to gain initial access to Confluence instances by creating unauthorized Confluence administrator accounts. Atlassian had first became aware of this vulnerability when multiple customers reported the malicious activity. Additionally Atlassian, confirmed that a known nation-state actor had exploited the vulnerability.
Vulnerability Name
CVE-2023-46604
Remote code execution vulnerability observed by Arctic Wolf in association with a ransomware campaign delivering a TellyouThePass variant.
CVE-2023-46604 At A Glance
A critical remote code execution (RCE) vulnerability that was observed by several vendors including Arctic Wolf being exploited in the wild shortly after the vulnerability's disclosure in late 2023. Arctic Wolf had observed several instances of active exploitation in association with a ransomware campaign delivering the TellYouThePass ransomware variant (https://arcticwolf.com/resources/blog/tellmethetruth-exploitation-of-cve-2023-46604-leading-to-ransomware/). At the time, over 3000 servers that were accessible externally were found to be running a vulnerable version of ActiveMQ (per shodan search).
Vulnerability Name
CVE-2023-36884
Remote code execution vulnerability exploited by Storm-0978.
CVE-2023-36884 At A Glance
A high severity remote code execution affecting Windows and Microsoft Office that was first disclosed by Microsoft in their July Patch Tuesday update. To exploit CVE-2023-36884, a threat actor would have to send a specially crafted file to a victim and convince them to take some sort of action. This vulnerability was used in a phishing campaign by Russian-nexus threat actor Storm-0978 to target defense and government entitites in Europe and North America using lures related to the Ukranian World Congress. At the time of it's disclosure, this vulnerability did not have an official patch and Microsoft fixed the vulnerability the following month.
Vulnerability Name
CVE-2023-3519
Remote code execution vulnerability used to target a critical infrastructure entity and install a webshell.
CVE-2023-3519 At A Glance
In July 2023, Citrix disclosed an actively exploited critical remote code execution (RCE) vulnerability in Citrix NetScaler ADC and NetScaler Gateway. The previous month, threat actors leveraged this zero-day vulnerability to install a webshell on the NetScaler ADC appliance of a critical infrastructure entity, which enabled the threat actors to exfiltrate Active Directory (AD) data.
Vulnerability Name
CVE-2023-42793
Russian Foreign Intelligence Service (SVR) affiliated threat actors targeted servers to exploit this vulnerability.
CVE-2023-42793 At A Glance
A critical vulnerability in JetBrains TeamCity that allows an unauthenticated attacker with HTTP(S) access to a TeamCity server to perform remote code execution (RCE). TeamCity is a continuous integration/continuous deployment (CI/CD) software platform for automating and managing the development of software. Since September 2023, threat actors affiliated to the Russian Foreign Intelligence Service (SVR) have been targeting servers hosting JetBrains TeamCity software. This allowed the threat actors to bypass authorization and conduct RCE.
Vulnerability Name
CVE-2023-28771
Used to build several Distributed Denial of Service (DDoS) botnets.
CVE-2023-28771 At A Glance
A critical remote code execution (RCE) affecting multiple Zyxel firewalls. Remote unauthenticated threat actors can achieve RCE by sending specially crafted packets to a vulnerable device. Throughout the middle of 2023, there was widespread exploitation globally of this vulnerability to build several Distributed Denial of Service (DDoS) botnets.
Vulnerability Name
CVE-2023-24880
Security feature bypass that allowed 100,000 downloads of malicious MSI files to deliver Magniber ransomware without any security warnings.
CVE-2023-24880 At A Glance
A medium severity security feature bypass vulnerability that was disclosed and patched by Microsoft in their March Patch Tuesday update. A threat actor could successfully exploit this vulnerability and evade Mark of the Web (MotW) tagging defenses by leveraging a specially crafted malicious file. Since January 2023, Google Threat Analysis Group (TAG) observed over 100,000 downloads of malicious MSI files to deliver Magniber ransomware without any security warnings.
Vulnerability Name
CVE-2023-46747
Critical remote code execution vulnerability that was observed chained with CVE-2023-46748
CVE-2023-46747 At A Glance
A critical remote code execution (RCE) vulnerability in F5's BIG-IP Traffic Management User Interface. If successfully exploited, a threat actor with network access to the vulnerable system could bypass the configuration utility authentication and execute arbitrary system commands. F5 observed the exploitation of this vulnerability chained with CVE-2023-46748 among their customers.
Vulnerability Name
CVE-2023-40044
Deserialization vulnerability that allows a threat actor to obtain remote code execution.
CVE-2023-40044 At A Glance
A maximum severity deserialization vulnerability that affects the Ad Hoc Transfer module within Progress WS_FTP Server, which allows a threat actor to obtain remote code execution (RCE). In late 2023, several vendors reported exploitation of this vulnerability observed in the wild.
Vulnerability Name
CVE-2023-26360
Remote code execution vulnerability used to compromise at least two servers belonging to a US government agency.
CVE-2023-26360 At A Glance
A threat actor can exploit this high severity remote deserialization of untrusted data flaw to achieve remote code execution (RCE). This vulnerability was disclosed by Adobe in April 2023 and stated that exploitation of this vulnerability has been observed in the wild. Subsequently between June and July 2023 this vulnerability was exploited to compromise at least two public-facing servers belonging to a Federal Civilian Executive Branch (FCEB) agency. Although NIST NVD rated this vulnerability as critical, the vendor rated it as a high severity vulnerability.
Vulnerability Name
CVE-2023-20273
Chained with CVE-2023-20198. Used after initial access to elevate privileges.
CVE-2023-20273 At A Glance
A privilege escalation vulnerability that is chained with the critical vulnerability CVE-2023-20198. In Cisco's observed exploitation, this vulnerability was used after initial access to leverage the new local user to elevate priviliges to root.
Vulnerability Name
CVE-2023-27997
Remote code execution vulnerability through heap-based buffer overflow.
CVE-2023-27997 At A Glance
A critical remote code execution (RCE) vulnerability in Forti OS and FortiProxy SSL-VPN disclosed in June 2023 that Fortinet observed being exploited in several instances. This vulnerability allows a threat actor to achieve RCE through a heap-based buffer overflow.
Vulnerability Name
CVE-2023-41265
HTTP tunneling vulnerability that leads to privilege esclation. Arctic Wolf observed this vulnerability exploited in a Cactus ransomware campaign.
CVE-2023-41265 At A Glance
An HTTP tunnelling vulnerability due to improper validation of HTTP headers in Qlik Sense, a cloud analytics and business intelligence platform. If successfully exploited, a threat actor could elevate their privileges and execute HTTP requests on the backend server hosting the software. Arctic Wolf observed this vulnerabiltiy being exploited in a Cactus ransomware campaign in November 2023 among several customers.
Vulnerability Name
CVE-2023-23397
Privilege escalation vulnerability leveraged by Forest Blizzard to provide unauthorized access to email accounts within exchange servers.
CVE-2023-23397 At A Glance
A critical privilege escalation vulnerability impacting Microsoft Outlook. A threat actor can successfully exploit this vulnerability and escalate privileges without user interaction by sending specially crafted emails that will trigger automatically when they are retrieved and processed by an Outlook client. Microsoft observed the Russian-nexus threat actor Forest Blizzard exploit this vulnerability to provide unauthorized access to email accounts within exchange servers.
9.8/10
Vulnerability Name:CVE-2023-47246
Remote code execution vulnerability exploited by Lace Tempest
Vulnerability Name
CVE-2023-47246
Remote code execution vulnerability exploited by Lace Tempest
CVE-2023-47246 At A Glance
In November 2023, SysAid was notified by Microsoft of a zero-day path traversal vulnerability allowing for remote code execution, which affects their on-premises ITSM solution. In the investigation conducted by SysAid, it was determined that the vulnerability was being actively exploited by a ransomware affiliate group known as Lace Tempest (DEV-0950), a group known for deploying the CL0P ransomware payload.
Vulnerability Name
CVE-2023-20887
Remote code execution vulnerability.
CVE-2023-20887 At A Glance
A critical severity remote code execution (RCE) vulnerability affecting Vmware Aria Operations for Networks. A remote threat actor can exploit this vulnerability by performing a command injection attack to achieve RCE with administrative privileges. Mass scanning in the wild was observed of this vulnerability utilzing a public proof of concept exploit.
Vulnerability Name
CVE-2023-0669
Remote code execution exploited by the Cl0p ransomware group to steal data from over 130 organizations.
CVE-2023-0669 At A Glance
A high severity zero-day remote code execution (RCE) vulnerability in Fortra GoAnywhere MFT (Managed File Transfer). In January 2023, Fortra discovered a threat actor using this vulnerability to target customer systems, and quickly implemented a temporary service outage to investigate. The Cl0p ransomware group claimed to exploit the vulnerability to steal data from over 130 organizations over the course of 10 days. Ransom notes were sent to upper-level executives of the victim companies.
Vulnerability Name
CVE-2023-41266
Path traversal vulnerability. Arctic Wolf observed this vulnerability exploited in a Cactus ransomware campaign.
CVE-2023-41266 At A Glance
A path traversal vulnerability stemming from improper user input validation which could allow a remote, unauthenticated threat actor to create an anonymous session by sending maliciously crafted HTTP requests. This anonymous session could allow them to send further requests to unauthorized endpoints. Arctic Wolf observed this vulnerabiltiy being exploited in a Cactus ransomware campaign in November 2023 among several customers. Although NIST NVD rated this vulnerability as a medium, the reporting entity labled it as high severity.
Vulnerability Name
CVE-2023-49103
Maximum severity information disclosure vulnerability with mass exploitation attempts since at least November 2023.
CVE-2023-49103 At A Glance
A maximum severity information disclosure vulnerability within the "graphapi" extension of OwnCloud, a file sharing service. This is due to the library that graphapi relies on. There have been reported of mass exploitation attempts by threat actors since at least November 2023. Although NIST NVD labeled this vulnerability as high severity, the reporting entity rated this vulnerability at a maximum critical CVSS score of 10.0.
Vulnerability Name
CVE-2023-33246
Critical remote code execution vulnerability used by a new version of the Dreambus botnet.
CVE-2023-33246 At A Glance
A critical remote code execution (RCE) vulnerability in Apache RocketMQ that was publicly disclosed in May 2023. Subsequently starting in June 2023, a new version of the DreamBus botnet was observed exploiting CVE-2023-33246 to infect devices by targeting RocketMQ's default 10911 port and at least seven other ports.
Vulnerability Name
CVE-2023-28252
Privilege escalation vulnerability leveraged in Nokoyawa ransomware intrusions.
CVE-2023-28252 At A Glance
A privilege escalation vulnerability impacting the Windows Common Log File System (CLFS) driver, which could allow a threat actor to obtain SYSTEM level privileges after successful exploitation. This vulnerability was disclosed by Microsoft in their April Patch Tuesday update. This vulnerability was exploited as a zero-day during and was leveraged in Nokoyawa ransomware intrusions.
Vulnerability Name
CVE-2023-29298
Improper access control vulnerability observed chained with CVE-2023-38203 to deliver web shells.
CVE-2023-29298 At A Glance
A high severity improper access control vulnerability that could lead to a security feature bypass. In July 2023 CVE-2023-29298 was observed being chained with CVE-2023-38203 to deliver web shells.
Vulnerability Name
CVE-2023-35078
Critical authentication bypass vulnerability used to target Norwegian organizations.
CVE-2023-35078 At A Glance
A critical authentication bypass vulnerability affecting Ivanti Endpoint Manager Mobile. This vulnerability allows allows unauthenticated access to specific API paths, which could allow a threat actor to obtain personal identifiable information (PII) such as names, phone numbers, and other mobile device details. From at least April 2023 through July 2023, threat actors exploited this vulnerability to gather information from several Norwegian organizations and compromise a Norwegian government agency's network.
2023 Most Exploited Vulnerabilities
Nowhere is the need for a renewed focus on cybersecurity fundamentals made clearer than in Arctic Wolf’s annual recap highlighting the most noteworthy, high-profile vulnerabilities. Discover how and why threat actors continue to have success leveraging unpatched, ignored, or otherwise forgotten vulnerabilities to wreak havoc on environments.
Reinforce Your Foundation. Amplify Your Resilience.

2023 Breaches in Review

2024 Arctic Wolf Labs Threat Report
AVAILABLE FOR DOWNLOAD
What 2023 Taught Us About Vulnerabilities
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