Microsoft Patch Tuesday — March 2020: Vulnerability disclosures and Snort coverage

An elevation of privilege vulnerability exists when DirectX improperly handles objects in memory, aka 'DirectX Elevation of Privilege Vulnerability'.

An elevation of privilege vulnerability exists when Azure DevOps Server and Team Foundation Services improperly handle pipeline job tokens, aka 'Azure DevOps Server and Team Foundation Services Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0815.

A remote code execution vulnerability exists when Active Directory integrated DNS (ADIDNS) mishandles objects in memory. An authenticated attacker who successfully exploited the vulnerability could run arbitrary code in the context of the Local System Account To exploit the vulnerability, an authenticated attacker could send malicious requests to an Active Directory integrated DNS (ADIDNS) server. The update addresses the vulnerability by correcting how Active Directory integrated DNS (ADIDNS) handles objects in memory.

An information disclosure vulnerability exists in the Remote Desktop Connection Manager (RDCMan) application when it improperly parses XML input containing a reference to an external entity, aka 'Remote Desktop Connection Manager Information Disclosure Vulnerability'.

A remote code execution vulnerability exists in the way that the ChakraCore scripting engine handles objects in memory, aka 'Scripting Engine Memory Corruption Vulnerability'. This CVE ID is unique from CVE-2020-0768, CVE-2020-0823, CVE-2020-0825, CVE-2020-0826, CVE-2020-0827, CVE-2020-0828, CVE-2020-0829, CVE-2020-0830, CVE-2020-0831, CVE-2020-0832, CVE-2020-0833.

CVE-2020-0787 is a privilege elevation flaw in the Windows Background Intelligent Transfer Service (BITS), which improperly handles symbolic links (CWE-269, CWE-59). An attacker who can already run low-privileged code on a machine — via a phishing payload or a chained remote-code-execution bug — can plant or manipulate symbolic links that BITS follows, causing the service to execute arbitrary code with SYSTEM-level privileges. Successful exploitation grants full control of the host, making this a common link in attack chains, and CISA notes known ransomware use. Because BITS ships by default with Windows, essentially every Windows client and server installation predating the vendor patch is affected. Exploitation is confirmed in the wild: the flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2022-01-28, and EPSS assigns a 42.5% probability of exploitation within 30 days (99th percentile).

Do: Apply Microsoft's updates for CVE-2020-0787 per vendor instructions (the flaw was addressed in Microsoft's March 2020 security updates) across all Windows clients and servers, prioritizing user workstations and internet-facing systems given known ransomware use. Since this is a local privilege escalation, pair patching with controls that block the initial foothold (MFA, email/phishing defenses, EDR). Verify remediation by confirming endpoints report the relevant update installed and no BITS symlink abuse indicators remain.

A denial of service vulnerability exists when the Visual Studio Extension Installer Service improperly handles hard links, aka 'Visual Studio Extension Installer Service Denial of Service Vulnerability'.

This vulnerability is caused when SharePoint Server does not properly sanitize a specially crafted request to an affected SharePoint server.An authenticated attacker could exploit this vulnerability by sending a specially crafted request to an affected SharePoint server, aka 'Microsoft SharePoint Reflective XSS Vulnerability'. This CVE ID is unique from CVE-2020-0891.

CVE-2020-0796 ('SMBGhost') is a memory-corruption (CWE-119) flaw in Microsoft's Server Message Block 3.1.1 (SMBv3) implementation, in which certain crafted requests — notably malformed compressed SMBv3 messages — can corrupt memory on the target. An unauthenticated remote attacker can trigger it by sending specially crafted SMBv3 packets directly to any SMB-enabled host, with no credentials or user interaction required. Successful exploitation yields arbitrary code execution on the target server or client, giving the attacker full control of the host, and the flaw was widely characterized as wormable because a compromised host can then attack others. Any Windows system running SMBv3 is affected — SMBv3 is enabled by default on modern Windows 10 and Windows Server builds, with Windows 10 versions 1903/1909 and Windows Server 2019/versions 1903/1909 identified in Microsoft's advisory. Exploitation is confirmed in the wild: the CVE is in CISA KEV (added 2022-02-10) with known ransomware use, EPSS assigns a 99.8% probability of exploitation within 30 days (100th percentile), and no public PoC is listed in the source data.

Do: Apply Microsoft's updates per vendor instructions immediately, prioritizing Windows 10 1903/1909 and Windows Server 2019/1903/1909 hosts and anything with SMB (TCP 445) reachable by untrusted networks. Until patched, disable SMBv3 compression per Microsoft's mitigation guidance (setting DisableCompression=1 under LanmanServer) and restrict inbound TCP 445 to trusted sources. Given confirmed ransomware use, hunt for post-exploitation activity on unpatched hosts.

An elevation of privilege vulnerability exists when the Diagnostics Hub Standard Collector or the Visual Studio Standard Collector allows file creation in arbitrary locations.To exploit the vulnerability, an attacker would first have to log on to the system.An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system.The update addresses the vulnerability by not permitting Diagnostics Hub Standard Collector or the Visual Studio Standard Collector to create files in arbitrary locations., aka 'Diagnostic Hub Standard Collector Elevation of Privilege Vulnerability'.

An elevation of privilege vulnerability exists when Azure DevOps Server and Team Foundation Services improperly handle pipeline job tokens, aka 'Azure DevOps Server and Team Foundation Services Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0758.

A remote code execution vulnerability exists when Microsoft Edge improperly accesses objects in memory, aka 'Microsoft Edge Memory Corruption Vulnerability'.

A remote code execution vulnerability exists in the way the scripting engine handles objects in memory in Microsoft browsers, aka 'Scripting Engine Memory Corruption Vulnerability'. This CVE ID is unique from CVE-2020-0768, CVE-2020-0823, CVE-2020-0825, CVE-2020-0826, CVE-2020-0827, CVE-2020-0828, CVE-2020-0829, CVE-2020-0831, CVE-2020-0832, CVE-2020-0833, CVE-2020-0848.

An elevation of privilege vulnerability exists when Windows Defender antimalware platform improperly handles hard links, aka 'Windows Defender Antimalware Platform Hard Link Elevation of Privilege Vulnerability'.

A remote code execution vulnerability exists in Microsoft Word software when it fails to properly handle objects in memory, aka 'Microsoft Word Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-0851, CVE-2020-0852, CVE-2020-0855, CVE-2020-0892.

A remote code execution vulnerability exists in Application Inspector version v1.0.23 or earlier when the tool reflects example code snippets from third-party source files into its HTML output, aka 'Remote Code Execution Vulnerability in Application Inspector'.

A spoofing vulnerability exists in Microsoft Visual Studio as it includes a reply URL that is not secured by SSL, aka 'Microsoft Visual Studio Spoofing Vulnerability'.

This vulnerability is caused when SharePoint Server does not properly sanitize a specially crafted request to an affected SharePoint server.An authenticated attacker could exploit this vulnerability by sending a specially crafted request to an affected SharePoint server, aka 'Microsoft SharePoint Reflective XSS Vulnerability'. This CVE ID is unique from CVE-2020-0795.

An elevation of privilege vulnerability exists in Service Fabric File Store Service under certain conditions, aka 'Service Fabric Elevation of Privilege'.

A cross-site-scripting (XSS) vulnerability exists when Microsoft Exchange Server does not properly sanitize a specially crafted web request to an affected Exchange server, aka 'Microsoft Exchange Server Spoofing Vulnerability'.