Old vulnerabilities are still a big problem

CVE-2012-0158 is a remote code execution flaw in Microsoft's MSCOMCTL.OCX, the Windows Common Controls ActiveX component, where improper handling of crafted input allows memory corruption and code execution. It is typically triggered when an application that uses the control (most commonly Microsoft Office) processes specially crafted content, such as a malicious document or file, meaning a victim usually has to open attacker-supplied content. Successful exploitation lets an attacker run arbitrary code and take complete control of the affected system with the privileges of the current user. Any Windows system carrying a vulnerable copy of MSCOMCTL.OCX — including systems where the control was redistributed by legacy applications — is affected, which makes the potential population very large. Exploitation is confirmed and ongoing: the flaw is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) with known ransomware use, and EPSS assigns it the maximum reported probability of exploitation within 30 days.

Do: Apply the Microsoft security update for MSCOMCTL.OCX (per vendor instructions, per CISA's required action) on all systems, prioritizing endpoints and servers that open Office documents. Because exploitation commonly arrives via malicious documents, treat unsolicited Office/RTF attachments with suspicion and verify that applications that redistribute MSCOMCTL.OCX have installed a patched copy. Scan the estate for the presence and version of MSCOMCTL.OCX, especially on legacy Windows/Office installations that may be missed by routine patching.

CVE-2012-0507 is an 'incorrect type' (type-confusion) vulnerability in the Concurrency component of Oracle's Java Runtime Environment that corrupts memory when crafted Java content is processed. It is triggered by running malicious Java content — classically via the browser Java plugin or an exploited Java application — allowing an attacker to execute arbitrary code with the privileges of the Java process. Anyone running an affected Oracle Java SE installation is exposed, which historically included the vast majority of desktops and many servers, with 2012-era campaigns hitting Mac users via Java exploits (e.g., the SabPub backdoor) and drive-by exploit kits. Exploitation is confirmed in the wild: the flaw is on CISA's Known Exploited Vulnerabilities catalog (added 2022-03-03) with known ransomware use, and EPSS assigns a 98.1% probability of exploitation within 30 days (100th percentile). CVSS has not been scored in the source data, but the combined KEV/EPSS signal marks this as actively and widely exploited.

Do: Apply Oracle's Java SE updates per CISA's required action — Oracle shipped the fix in its February 2012 Critical Patch Update, so any current, fully patched Java release clears the flaw; verify no legacy unpatched Java builds (including Apple-delivered Java on macOS, given the 2012 OS X exploitation campaigns) remain on endpoints. Remove or disable the Java browser plugin where it is not required, and restrict execution of untrusted applets and Java Web Start content.

Oracle Java SE's Java Runtime Environment contains an unspecified flaw in its Hotspot component that allows remote attackers to affect confidentiality, integrity, and availability — characterized by CISA as arbitrary code execution. The available data does not document the exact trigger beyond 'unknown vectors related to Hotspot,' but flaws in the JVM's execution engine of this type are typically reached remotely by having the runtime process malicious Java content. A successful attacker gains code execution in the context of the process running the JVM, taking control of the affected host. Any deployment running affected, unpatched Oracle Java SE — particularly legacy JRE installs — is affected. The vulnerability is in CISA's Known Exploited Vulnerabilities catalog (added 2022-03-03) with known ransomware use and a 93.7% EPSS probability of exploitation in the next 30 days, confirming active in-the-wild exploitation, though the reviewed data lists no public PoC.

Do: Per CISA's required action, apply updates per vendor instructions: upgrade every Oracle Java SE installation to a currently supported patched release and inventory for legacy JRE builds that predate the 2012 Hotspot fix. Disable or restrict the Java browser plugin where it is not needed, and given known ransomware use, prioritize legacy Java systems for patching and threat-hunting.

CVE-2013-0074 is a double dereference (dangling pointer) flaw in Microsoft Silverlight: the runtime does not properly validate pointers while rendering HTML objects, corrupting memory when a malformed pointer is dereferenced. An attacker triggers it by getting a user to view a web page or open content that loads a crafted Silverlight application, with no authentication or special privileges required. Successful exploitation allows remote code execution in the context of the logged-on user, potentially letting an attacker install programs, steal data, or create accounts. Any system with the Silverlight runtime installed is affected; per CISA's required action the product is end-of-life (Silverlight support ended in October 2021) and should be disconnected if still in use. Exploitation is confirmed: the flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2022-05-25 with known ransomware use, and EPSS puts its 30-day exploitation probability at 81% (100th percentile), despite the absence of a known public PoC.

Do: Audit inventories and endpoints for any Silverlight runtime or .xap-consuming applications and remove/uninstall the plugin where possible; if the runtime must be retained, ensure the March 2013 MS13-022 security update or a later Silverlight 5.1 runtime is installed. Because Silverlight is end-of-life with no further patches, follow CISA's required action: disconnect or retire any remaining Silverlight-dependent applications, and block known exploit-kit delivery vectors (drive-by web content) with updated browser and email filtering.

GNU Bash through version 4.3 improperly processes trailing strings that follow function definitions inside environment variable values, allowing injected commands to run (CWE-78, OS command injection); this flaw is widely known as 'Shellshock'. An attacker triggers it by supplying a crafted environment variable to any service that invokes Bash, most notably CGI web handlers but also SSH, DHCP clients, and other software that sets variables and spawns the shell. Successful exploitation yields arbitrary code execution with the privileges of the Bash process on the target host. Any Linux, Unix, or similar system running an unpatched Bash through 4.3 is affected, including web servers, appliances, and embedded devices that ship the shell. Exploitation is confirmed in the wild: the flaw is in CISA's KEV (added 2022-01-28) with a required action to apply vendor updates, and EPSS assigns it a 100% probability of exploitation within 30 days, so patching is urgent.

Do: Apply Bash updates per your OS vendor's instructions, as required by the CISA KEV listing, ensuring the installed shell is a patched build newer than the unpatched 4.3-era code. Prioritize internet-exposed systems that pass environment variables to Bash, especially CGI-based web servers, and audit embedded appliances and other Linux/Unix hosts that may have been missed by standard patching.

CVE-2017-0143 is a remote code execution flaw in the SMBv1 server implementation shipped with a wide range of Windows releases; it is one of the March 2017 'MS17-010' SMBv1 bugs (an EternalBlue-family flaw) and is distinct from CVE-2017-0144, -0145, -0146 and -0148. An attacker triggers it by sending specially crafted packets to a target's SMBv1 service over the network, gaining the ability to execute arbitrary code on the host. Because SMB is commonly reachable inside enterprise networks (and sometimes from the internet), exploitation has enabled wormable spread, ransomware (WannaCry), coin miners (Adylkuzz), and DOUBLEPULSAR backdoor implants. Anyone running unpatched, SMBv1-enabled systems from the affected list is exposed: Windows from Vista/Server 2008 through Windows 10 1607 and Server 2016, plus third-party products embedding Windows, including Philips IntelliSpace Portal and Siemens ACUSON/syngo/Versant medical systems. Exploitation is heavily confirmed in the wild: the Buckeye group used the tools before the Shadow Brokers leak, followed by mass exploitation by WannaCry, Adylkuzz, Uiwix and EternalRocks; the flaw is in CISA's KEV (added 2021-11-03, ransomware use known) and EPSS is 93.3%.

Do: Apply Microsoft's MS17-010 security updates (March 2017 cumulative updates or later) to all listed Windows versions, per the CISA KEV required action. Disable SMBv1 where feasible, block or restrict inbound TCP 445 from untrusted networks, and check exposed hosts for DOUBLEPULSAR implants; public Metasploit modules (EternalBlue/EternalRomance/EternalSynergy/EternalChampion) can be used to verify exploitability. For Philips IntelliSpace Portal and Siemens ACUSON/syngo/Versant medical systems, apply the vendors' MS17-010 firmware/advisory updates.

CVE-2017-0144 is a remote code execution flaw in the SMBv1 server component of Microsoft Windows, commonly known as EternalBlue, and one of the SMB flaws fixed by Microsoft in the March 2017 MS17-010 bulletin. An attacker who can reach the SMB service over the network sends specially crafted packets that trigger memory corruption in the SMBv1 implementation, gaining the ability to execute arbitrary code on the target without user interaction. Successful exploitation yields full system compromise and has been heavily weaponized for wormable spread and ransomware delivery, notably via the leaked NSA exploit and in the WannaCry/NotPetya-era outbreaks, and the flaw has repeatedly been bundled into botnets and ransomware tooling since. Anyone running unpatched Windows Vista SP2 through Windows 10 1607 / Windows Server 2016 with SMBv1 enabled is affected, as are Siemens medical and laboratory devices (ACUSON ultrasound, syngo SC2000, Tissue Preparation System, VERSANT kPCR systems) whose firmware depends on SMBv1. Exploitation is actively ongoing: the flaw is in CISA's Known Exploited Vulnerabilities catalog (added 2022-02-10) with known ransomware use, carries a 99.2% EPSS exploitation probability (100th percentile), and multiple public exploits and PoCs are available.

Do: Apply the Microsoft MS17-010 (March 2017) security updates on every listed Windows version and the corresponding Siemens firmware updates for ACUSON, syngo SC2000, Tissue Preparation System, and VERSANT kPCR devices, per CISA's required action to apply vendor updates. Where patching is not yet possible, disable SMBv1 or block inbound TCP 445 (and UDP 137/138) at network boundaries and isolate legacy/medical systems from the internet. Sweep exposed and legacy hosts for compromise indicators, including DOUBLEPULSAR implants delivered over SMB, as public tooling for detecting and neutralizing this implant is available.

CVE-2017-0199 is a remote code execution vulnerability in Microsoft Office and WordPad that stems from improper parsing of specially crafted files. Attackers trigger it by getting a user to open a malicious document, after which attacker-controlled code executes with the privileges of the logged-in user. Anyone running the affected Microsoft Office or WordPad software is exposed, and CISA notes the flaw has been leveraged in ransomware campaigns; no CVSS score is available in the source data. The flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2021-11-03, and EPSS assigns a 99.9% probability of exploitation within 30 days (100th percentile), indicating active, ongoing exploitation.

Do: Apply Microsoft's security updates for Office and Windows per vendor instructions, as required by CISA's KEV catalog; the flaw was publicly reported as fixed in Microsoft's April 2017 security updates. Until patched, treat unsolicited Office documents and email attachments as high-risk, since exploitation requires a user to open a crafted file. Verify that all Office and WordPad installations across the estate—especially endpoints that handle untrusted documents—have received the update.

CVE-2017-11882 is a memory corruption vulnerability (CWE-119) in Microsoft Office, residing in the legacy Microsoft Equation Editor component (EQNEDT32.EXE), that allows remote code execution in the context of the current user. Attackers trigger it by persuading a user to open a crafted document, most commonly an RTF file or other Office document carrying a malicious embedded equation object, which overflows a buffer while the equation content is parsed. Successful exploitation lets the attacker run arbitrary code with the privileges of the signed-in user, a typical foothold for malware delivery and, per CISA, for ransomware operations. Any environment running affected Microsoft Office builds is exposed; the source data does not enumerate specific affected version ranges. The flaw is confirmed exploited in the wild: it was added to the CISA Known Exploited Vulnerabilities catalog on 2021-11-03 with known ransomware use and holds a 99.9% EPSS score (percentile 100), though the source data lists no public PoC.

Do: Apply Microsoft's Office security updates (November 2017 or later) across all endpoints, prioritizing this KEV-listed flaw given its known ransomware use. On systems that cannot yet be patched, disable or unregister the legacy Equation Editor (EQNEDT32.EXE) and consider blocking or warning on RTF attachments as interim mitigations. Check for indicators of abuse such as EQNEDT32.EXE spawning unexpected child processes after document opens.

CVE-2017-8570 is a remote code execution vulnerability in Microsoft Office caused by improper handling of embedded OLE objects (composite monikers) in memory, and it is tracked separately from the related CVE-2017-0243. An attacker triggers it by embedding a crafted moniker object in a document, most commonly a PowerPoint .ppsx slide-show file, and persuading a user to open it; the CVSS vector confirms user interaction is required. Successful exploitation lets the attacker run arbitrary code with the victim's privileges, enabling malware delivery, data theft, and follow-on activity. Any user or organization running affected Office builds that open untrusted documents is in scope, and public reporting ties the bug to high-volume maldoc toolkits (e.g., EtterSilent, ThreadKit) and targeted attacks, including one against Ukrainian organizations. Exploitation is confirmed in the wild: CISA added it to the KEV catalog on 2022-02-25, EPSS puts the 30-day exploitation probability at 89.9% (100th percentile), and public PoCs exist.

Do: Apply Microsoft's June 2017 (or later) security updates to all Office installations and audit the estate for outdated builds, since CISA KEV and EPSS data show this bug is still exploited years after the patch. As an interim mitigation, block or sandbox .ppsx (PowerPoint Show) email attachments, which are the primary delivery vector, and warn users about Office files triggering embedded object content. Prioritize remediation per CISA's KEV required action: apply updates per vendor instructions.

A memory-corruption flaw (out-of-bounds write, CWE-787) in the legacy Equation Editor component (EQNEDT32.EXE) shipped with Microsoft Office 2007, 2010, 2013, and 2016 allows remote code execution due to improper handling of objects in memory. An attacker triggers it by persuading a user to open a specially crafted document (for example an RTF or DOCX containing a malformed embedded equation object), causing the Equation Editor process to corrupt memory when the file is opened in Word; the user-interaction requirement is reflected in the CVSS 3.1 vector (AV:L/UI:R). Successful exploitation gives the attacker code execution in the context of the current user, with high impact on confidentiality, integrity, and availability (CVSS 3.1 score 7.8, High). Any user of the affected Office versions, the Office Compatibility Pack, or Word on an unpatched system is affected. Exploitation is confirmed in the wild: the flaw is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) with known ransomware use, carries a 93.3% EPSS probability of exploitation within 30 days, and multiple public analyses and proof-of-concepts exist.

Do: Apply Microsoft's January 2018 security updates for Office 2007, 2010, 2013, and 2016 and the Office Compatibility Pack, and verify the legacy Equation Editor executable (EQNEDT32.EXE) on endpoints has been patched or removed (Microsoft later retired the component). Because the flaw is exploited in the wild and used in ransomware campaigns, prioritize remediation per CISA KEV required action and hunt for Word spawning EQNEDT32.EXE or unexpected child processes when documents are opened. Until patched, open untrusted documents in Protected View and treat email-delivered RTF/DOCX attachments as untrusted.

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-2018-8174 is an out-of-bounds write (CWE-787) in the Microsoft Windows VBScript engine, caused by the way it handles objects in memory. An attacker triggers it by convincing a user to visit a specially crafted website or open crafted content that invokes the VBScript engine (for example via Internet Explorer or a document preview), requiring user interaction. Successful exploitation yields remote code execution with the privileges of the logged-on user, enabling program installation, data theft and account takeover. All listed Windows client and server releases are affected: Windows 7, 8.1, RT 8.1, Windows 10 (1607-1803), and Windows Server 2008/2008 R2, 2012/2012 R2, 2016. Exploitation is in the wild: the flaw was fixed in the May 2018 Patch Tuesday, is listed in CISA KEV with known ransomware use, and public PoCs (0patch, ExploitDB 44741) and exploit kit usage have been documented; EPSS puts its 30-day exploitation probability at 88.5%.

Do: Apply Microsoft's May 2018 security updates (and any later cumulative or Extended Security Updates) to every listed Windows client and server release, as required by the CISA KEV listing, prioritizing internet-reachable and user-facing systems given known ransomware use. Upgrade out-of-support platforms (Windows 7/8.1/RT 8.1, Server 2008/2008 R2, 2012/2012 R2) to supported builds or ensure ESU coverage. As interim mitigation, block VBScript execution in Internet Explorer web zones using Microsoft's documented Group Policy/registry settings, and hunt for prior exploitation on legacy systems.

Ivanti Pulse Connect Secure, an enterprise SSL VPN appliance, contains an arbitrary file read vulnerability (CWE-22, path traversal) that requires no authentication. An unauthenticated remote attacker with network access to the appliance over HTTPS can send a specially crafted URI containing traversal sequences to read arbitrary files from the device. The attacker gains access to sensitive appliance files, potentially including configuration or credential material useful for further compromise, and CISA records known ransomware use of this flaw. Any organization running Pulse Connect Secure, especially gateways exposed to the internet for remote access, is affected. Exploitation is established: CISA added the flaw to its Known Exploited Vulnerabilities catalog on 2021-11-03 with known ransomware use, EPSS assigns a 100% probability of exploitation in the next 30 days, and no public PoC is known.

Do: Apply updates per Ivanti's instructions, the required action in the CISA KEV entry, prioritizing internet-facing Pulse Connect Secure gateways, and consult the vendor advisory for the applicable fixed release since no version range is provided here. Where patching is not immediate, restrict HTTPS access to the appliance and hunt for signs of exploitation (unexpected file reads, anomalous VPN logins or sessions, and follow-on ransomware activity), as CISA reports known ransomware use.

CVE-2019-2725 is an easily exploitable injection flaw (CWE-74) in the Web Services subcomponent of Oracle WebLogic Server within Oracle Fusion Middleware, publicly documented as affecting WebLogic 10.3.6.0, 12.1.3.0, 12.2.1.1 and 12.2.1.3. It is triggered when an unauthenticated remote attacker sends attacker-controlled XML over HTTP to the WebLogic Web Services async response endpoint (the /_async/AsyncResponseService servlet), which processes the input unsafely. Successful attacks give the attacker takeover of the affected WebLogic server (remote code execution); in the 2019 exploitation wave this was used to install cryptocurrency miners and deploy ransomware. Any organization running affected Oracle WebLogic Server versions is exposed, with the greatest risk where the async/Web Services endpoints are reachable, especially on internet-facing servers. Exploitation is confirmed in the wild: CISA added the CVE to its KEV catalog on 2022-01-10 with ransomware use known and requires applying vendor updates, the EPSS probability of exploitation is 100% (100th percentile), and no public PoC is catalogued.

Do: Apply Oracle's updates per vendor instructions: this CVE was fixed by Oracle's April 2019 out-of-band WebLogic patch and is covered by subsequent Critical Patch Updates, so bring affected WebLogic 10.3.6.0/12.1.3.0/12.2.1.x servers to a patched level (CISA KEV requires this action). Until patched, restrict or remove the async response service deployments (wls9_async_response.war / wls_wsee_async_response.war, exposing the /_async/AsyncResponseService endpoint) and keep WebLogic ports off the internet. Also review logs for unsolicited POSTs to /_async/AsyncResponseService and for signs of dropped miners or ransomware payloads.

CVE-2020-1472, widely known as "Zerologon," is an elevation-of-privilege flaw in how the Netlogon secure channel is established over the Netlogon Remote Protocol (MS-NRPC) on Microsoft domain controllers. An unauthenticated attacker with network reachability to a domain controller sends specially crafted Netlogon messages to establish a vulnerable secure channel and then runs a specially crafted application on the network to obtain domain administrator access. Successful exploitation yields domain administrator privileges, effectively full compromise of the Active Directory environment, and the flaw is known to be used in ransomware operations. Any organization running affected Windows Server versions (2008 through 20H2) as domain controllers is exposed, along with environments using Netlogon implementations from Samba and distributions or products from Fedora, openSUSE, Canonical (Ubuntu), Debian, Synology, and Oracle. Exploitation is highly active: a public Zerologon PoC/exploit is available, the flaw is on CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03, with known ransomware use), and EPSS estimates a 99.4% probability of exploitation within 30 days.

Do: Apply the vendor updates on all domain controllers and other affected systems immediately, following Microsoft's two-phase Netlogon secure channel guidance (the enforcement phase of the phased rollout began in Q1 2021). Audit Netlogon secure-channel connections and event logs for clients still using vulnerable connections before enabling full enforcement, and install updated packages for Samba and other Netlogon implementations from Fedora, openSUSE, Ubuntu, Debian, Synology, and Oracle. Given known ransomware use, prioritize patching any domain controller reachable from user networks, VPNs, or the internet.

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-2021-26855 is a server-side request forgery flaw (CWE-918) in Microsoft Exchange Server that allows an unauthenticated remote attacker to send specially crafted HTTP requests and have the Exchange server process them as itself, disclosing sensitive session information. When chained with sibling Exchange flaws (the 'ProxyLogon' chain), it yields authentication bypass and arbitrary file write, escalating to full remote code execution with SYSTEM-level privileges on the on-premises Exchange server. Any organization running an affected on-premises Exchange server reachable over HTTP/HTTPS (typically outbound webmail) is exposed; Exchange Online was not affected. Exploitation is confirmed in the wild at large scale: the flaw was mass-exploited beginning in early 2021 (notably by the HAFNIUM group), is on the CISA KEV with documented ransomware use, and has a maximum EPSS score of 100% (100th percentile), despite no public PoC listing.

Do: Apply the vendor's March 2021 Exchange security updates (or later cumulative updates) immediately, per the CISA required action; until patched, limit Exchange (ECP/OWA) exposure to the internet via firewall/VPN rules. Hunt for compromise: review IIS logs for unrecognized authenticated activity against FrontEnd HttpProxy endpoints, and check for malicious files or webshells under inetpub\wwwroot\aspnet_client, given the 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.

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.