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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-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-2017-8759 is a code injection flaw (CWE-94) in Microsoft .NET Framework's handling of SOAP WSDL parsing, in which untrusted content referenced by a document or application is parsed and used during object instantiation, allowing attacker-controlled code to run. An attacker triggers it by delivering a specially crafted document — notably a Microsoft Word file referencing a malicious WSDL URL — and gets code execution when the document is opened and .NET downloads and parses the referenced content. Successful exploitation gives the attacker code execution with the privileges of the current user, sufficient to install malware, steal data, or facilitate further compromise. Any Windows system running .NET Framework versions 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, or 4.7 is affected, which at disclosure covered the vast majority of Windows desktops and servers in use. The flaw was a zero-day exploited in the wild at disclosure (September 2017, used in targeted attacks including BlackOasis), is listed in CISA's Known Exploited Vulnerabilities catalog, and public proof-of-concept exploits are available.

Do: Apply Microsoft's security updates addressing this vulnerability to all affected .NET Framework versions on Windows endpoints and servers, per the CISA KEV required action. Prioritize user-facing systems that open documents and are internet-exposed, and verify installed .NET Framework versions before and after remediation. As a compensating control, exercise caution with untrusted documents and block or inspect outbound fetches of WSDL references embedded in Office files.