Fortinet VPN bug tops CISA’s list of most exploited vulnerabilities in 2022

CVE-2018-13379 is a path traversal flaw (CWE-22) in the Fortinet FortiOS SSL VPN web portal that allows an unauthenticated attacker to download FortiOS system files via specially crafted HTTP resource requests. By traversing directories through crafted requests to the exposed web portal, the attacker can retrieve sensitive files, a technique publicly documented as yielding the SSL VPN session file containing usernames and passwords in plaintext. Any organization running the SSL VPN web portal on a FortiGate appliance is affected, and risk is highest where the portal is directly reachable from the internet. The flaw is confirmed in the wild: it was added to the CISA KEV catalog on 2021-11-03 with known ransomware use, and EPSS assigns it a 100% probability of exploitation within 30 days. No public PoC is listed in the provided data, but credential theft tied to this bug has been widely reused by threat actors.

Do: Apply the patched FortiOS release per Fortinet's vendor advisory immediately, as this is a CISA KEV required action; if the fixed version is not known from this data, follow Fortinet's FG-IR-18-384 advisory for the correct upgrade path. Rotate SSL VPN credentials and review VPN access logs for path-traversal requests, since successful exploitation exposes plaintext session credentials, and restrict SSL VPN portal exposure to trusted sources where possible.

CVE-2021-26084 is an OGNL injection vulnerability (CWE-917) in Atlassian Confluence Server and Data Center that may allow an unauthenticated attacker to execute arbitrary code. Any organization running Confluence Server or Data Center is potentially affected. It is significant because it is listed in CISA's Known Exploited Vulnerabilities catalog with known ransomware use, and EPSS assigns a 100.0% probability of exploitation within 30 days (100th percentile).

Do: Apply updates to Confluence Server and Data Center per Atlassian's instructions, which is the required action in the CISA KEV listing. Prioritize remediation given confirmed in-the-wild exploitation and known ransomware use.

CVE-2021-31207 is a security feature bypass in Microsoft Exchange Server, classified as an unrestricted file-write issue (CWE-434) that lets an attacker bypass intended restrictions and write files of their choosing to the server. It is the final bug in the ProxyShell chain: chained with the autodiscover SSRF and PowerShell backend elevation flaws, it allows an unauthenticated attacker to reach the Exchange PowerShell API, write arbitrary files such as an ASPX webshell, and execute code with SYSTEM privileges. A successful attacker gains full control of the on-premises Exchange server, including mailbox access, stolen credentials, and a foothold for lateral movement; the bug has been used to deploy ransomware and keyloggers. On-premises deployments of Microsoft Exchange Server (2013, 2016, and 2019 per vendor advisories) are affected, while Exchange Online/cloud mailboxes are not. Exploitation is essentially certain and ongoing: the flaw is in CISA's KEV (added 2021-11-03) with known ransomware use, public ProxyShell PoC/exploit code is available, and EPSS puts the 30-day exploitation probability at 99.8%.

Do: Apply Microsoft's July 2021 security updates for Exchange Server 2013, 2016, and 2019 (or any later security/cumulative update) per vendor instructions, and restrict untrusted access to Exchange's autodiscover and PowerShell endpoints. Hunt for ASPX webshells under the Exchange FrontEnd directories and review IIS logs for autodiscover.json requests chaining PowerShell, since many servers were compromised before patching. Given known ransomware use and KEV listing, treat any server that was unpatched or internet-exposed during the exploitation window as potentially compromised.

Microsoft Exchange Server contains a server-side request forgery (SSRF, CWE-918) in the Autodiscover service that unauthenticated remote attackers can reach over HTTP. This flaw is the first stage of the widely documented 'ProxyShell' chain, in which the SSRF is combined with privilege escalation and an arbitrary file write in the Exchange PowerShell backend to achieve unauthenticated remote code execution on the server. An attacker who successfully exploits it gains the ability to run code on the Exchange server, and ransomware operators (e.g., Cuba ransomware) leveraged this chain to deploy payloads. Organizations running on-premises Microsoft Exchange Server (2013, 2016, and 2019 per the vendor's advisories) are affected; hosted Exchange Online is a separately managed cloud service. Exploitation is confirmed in the wild: CISA added the flaw to the KEV catalog on 2021-11-03 with known ransomware use, and EPSS assigns it a 100% probability of exploitation within 30 days (100th percentile).

Do: Apply Microsoft's July 2021 (or later) Exchange Server security updates, which include the ProxyShell fixes, to all on-premises servers. If patching is delayed, restrict internet access to the Autodiscover/EWS frontend endpoints and consider the URL Rewrite mitigation Microsoft published for ProxyShell. Given the KEV listing and known ransomware use, treat internet-facing, unpatched Exchange servers as potentially compromised and hunt for webshells, unusual Exchange processes, and suspicious account or mailbox activity.

CVE-2021-40539 is a critical (CVSS 9.8) authentication bypass in the REST API of Zoho ManageEngine ADSelfService Plus, caused by use of an incorrectly resolved name or reference (CWE-706). An unauthenticated, network-adjacent or internet-reachable attacker sends specially crafted requests to the product's REST API, bypassing authentication, and can chain the bypass to full remote code execution with no privileges or user interaction required. Successful exploitation yields complete compromise of the self-service portal server (high impact to confidentiality, integrity and availability); public reporting and vendor notes document attackers dropping malicious code and web shells onto vulnerable servers. Any organization running ManageEngine ADSelfService Plus build 6113 or earlier is affected, which typically means enterprise Microsoft Active Directory environments running this widely deployed self-service password/SSO portal. Exploitation is confirmed in the wild: the flaw was added to CISA KEV on 2021-11-03 with known ransomware use, EPSS puts the 30-day exploitation probability at 99% (100th percentile), Microsoft warned that Chinese threat actors were actively exploiting it, a public proof-of-concept is available, and it ranked among CISA's most routinely exploited vulnerabilities.

Do: Immediately upgrade ManageEngine ADSelfService Plus to a fixed build newer than 6113 per the vendor's update instructions, as required by CISA. Because exploitation predates patching and the flaw has been used to drop malicious code, check ADSelfService Plus servers for web shells, unexpected scheduled tasks, and unexplained accounts/processes, and hunt for indicators from the published analyses. Where possible, restrict internet exposure of the ADSelfService Plus REST API while patching, prioritized for externally reachable instances.

Apache Log4j2, an extremely widely used Java logging library, fails to protect its JNDI lookup feature against attacker-controlled JNDI-related endpoints (CWE-20, CWE-502), so crafted text processed by the logger causes the Java runtime to fetch and load attacker-supplied objects, leading to remote code execution. The flaw is triggered whenever attacker-controlled input reaches the logging API and is parsed for JNDI lookups, a pattern common in web servers and enterprise Java applications that log user-supplied fields such as headers or form values. Successful exploitation yields arbitrary code execution under the privileges of the affected application, giving attackers a foothold for lateral movement, data theft, and ransomware deployment. Any Java application or product that ships or bundles an affected Apache Log4j2 release is exposed, making this one of the most broadly deployed vulnerabilities ever disclosed. Exploitation is confirmed in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2021-12-10 with known ransomware use, and EPSS assigns a 100% probability of exploitation within 30 days.

Do: Inventory all Java applications and dependencies for Apache Log4j2 and apply the vendor's patched updates, or remove affected assets from the network, as required by CISA's KEV catalog. Where updates are not yet available, use the temporary mitigations in CISA's ED-22-02 recommended-mitigation guidance, such as disabling message lookups, only until patches are applied. Prioritize internet-facing and business-critical systems and hunt for exploitation activity given known ransomware use.

CVE-2022-22954 is a server-side template injection vulnerability (CWE-94) in VMware Workspace ONE Access and VMware Identity Manager that allows remote code execution on affected appliances. It is triggered when attacker-controlled input is passed into a server-side template engine, allowing injected template directives to be evaluated and executed as code on the server. A successful attacker gains the ability to run arbitrary code on the identity appliance, and CISA notes the flaw has been used in ransomware campaigns, so compromise can serve as an initial foothold for broader enterprise intrusion. Any organization running Workspace ONE Access or Identity Manager, including deployments where the Identity Manager component is bundled into VMware Horizon environments, is potentially affected, though the source data does not specify affected version ranges. The vulnerability was added to CISA's Known Exploited Vulnerabilities catalog on 2022-04-14 with ransomware use confirmed and a required action to apply vendor updates, and EPSS currently assigns it a 100% probability of exploitation within 30 days (100th percentile); no public PoC is known.

Do: Apply the patches published in VMware advisory VMSA-2022-0011 (April 2022) to Workspace ONE Access and Identity Manager appliances as required by the CISA KEV listing, prioritizing internet-facing instances, and restrict or remove public exposure until patched. Review appliance and web-server logs for template-injection probes and unexpected processes spawned by the identity service, and investigate any indications of compromise for follow-on ransomware or lateral-movement activity.

VMware Workspace ONE Access, VMware Identity Manager and vRealize Automation virtual appliances contain a local privilege escalation flaw (CWE-250, execution with unnecessary privileges): support scripts shipped with the appliances have improperly set permissions and run with elevated privileges. An attacker who already has some form of local or shell access to an affected appliance can modify or abuse these scripts to execute code as root (per VMware's advisory), gaining full control of the appliance, its identity/directory data and a platform for persistence and pivoting. Organizations running these VMware identity- and cloud-automation appliances are affected, since the weakness is in the appliance software itself; risk is highest where the appliances are reachable or where this bug is chained with other recently disclosed VMware appliance vulnerabilities. The flaw is known exploited in the wild: it was added to CISA's Known Exploited Vulnerabilities catalog on 2022-04-15, and EPSS assigns a high 35.8% probability of exploitation within 30 days (98th percentile), although no public PoC is known and ransomware use is unconfirmed.

Do: Apply the patched appliance releases per VMware's instructions, as required by CISA's KEV listing; until patched, restrict local, shell and management-plane access to Workspace ONE Access, Identity Manager and vRealize Automation appliances, and review them for unexpected root-level activity or modified support scripts. Treat this as actively exploited and prioritize patching alongside the other flaws fixed in the same VMware advisory.

Atlassian Confluence Server and Data Center contain an unauthenticated remote code execution flaw caused by improper neutralization of expression-language (OGNL) input (CWE-917): an attacker with network access to the application can submit a crafted request that is evaluated as an expression and executed by the server. Successful exploitation lets a remote, unauthenticated attacker run arbitrary code with the privileges of the Confluence process, without any credentials. All organizations running self-managed Confluence Server or Data Center are affected, particularly instances exposed to the internet; Confluence Cloud is not listed among the affected products. Exploitation is confirmed in the wild: the flaw was added to CISA's KEV on 2022-06-02 with ransomware use marked as known, and EPSS assigns a 100% probability of exploitation within 30 days (100th percentile). CVSS has not yet been scored in this data, but the KEV listing and known ransomware use make unpatched, internet-facing instances a top-priority patching target.

Do: Immediately upgrade to the patched Confluence release specified in Atlassian's 2022-06-02 security advisory, and until patched follow the CISA required action to block all internet traffic to and from affected instances. Because in-the-wild exploitation and ransomware use are confirmed, also hunt for compromise indicators on both patched and unpatched hosts, such as webshells, unexpected child processes of the Confluence service, and unusual outbound connections.

CVE-2022-30190 (Follina) is a remote code execution flaw in the Microsoft Windows Support Diagnostic Tool (MSDT) when MSDT is invoked through its ms-msdt URL protocol by a calling application such as Microsoft Word. Attackers trigger it by luring a user into opening a malicious document — typically a Word/RTF file whose link or remotely linked template launches the ms-msdt: URI with attacker-supplied commands — and CVSS 3.1 rates it 7.8 with a local attack vector and required user interaction. A successful exploit runs arbitrary code with the privileges of the calling application, allowing the attacker to install programs, view, change or delete data, or create new accounts in the user's context. Per the CISA data, affected platforms are Windows 7, 8.1 and RT 8.1, Windows 10 versions 1507 through 21H2, Windows 11 21H2, and Windows Server 2008 and 2012 — essentially any Windows installation that ships MSDT, with Office/Word as the common delivery vector. Exploitation is confirmed in the wild: Microsoft acknowledged it as an exploited zero-day, CISA added it to the KEV on 2022-06-14 with known ransomware use, EPSS puts the 30-day exploitation probability at 99.2% (99th percentile), and contemporaneous reporting also tied its use to espionage actors including APT28.

Do: Apply Microsoft's security updates per vendor instructions (the fix shipped in the June 2022 Patch Tuesday releases for the affected Windows versions), as required by CISA's KEV. If patching must be delayed, follow Microsoft's documented mitigation to disable the MSDT URL protocol (remove or restrict the HKEY_CLASSES_ROOT\ms-msdt registry key) and enforce Office Protected View / block Word from fetching remote templates over the network. Hunt for exploitation by checking whether Office processes (WINWORD.exe) launch msdt.exe or sdiagnhost.exe, or whether ms-msdt: URIs are invoked unexpectedly.