Authors of Purple Fox EK adds 2 Microsoft exploits

CVE-2015-1701 is a local elevation-of-privilege vulnerability in Win32k.sys, the Windows kernel-mode driver, that allows a local attacker to execute arbitrary code with kernel-level (SYSTEM) privileges. It is triggered by running a specially crafted application on an affected Windows system, where mishandled user-mode objects in the kernel let the attacker escape a limited user context. An attacker who already has a normal user foothold can escalate to full system rights, enabling persistence and lateral movement; in documented campaigns it was chained with other exploits to move from remote code execution to complete system compromise. Any unpatched Microsoft Windows installation carrying the vulnerable Win32k.sys is affected; the CISA description explicitly cites Microsoft Windows Server, and this kernel-mode driver ships with Microsoft's Windows server and client releases. Exploitation is confirmed in the wild: CISA added the CVE to the Known Exploited Vulnerabilities catalog on 2022-03-03 with known ransomware use, and the 56.2% EPSS (99th percentile) indicates a high probability of exploitation in the next 30 days; no public PoC is known.

Do: Apply Microsoft's Windows security update for this CVE (bulletin MS15-051, released with the April 2015 Patch Tuesday) on all Windows client and server systems, prioritizing servers, terminal services hosts, and any machine where untrusted users can execute code, and audit the estate for legacy systems still missing the fix. As an interim control where patching is delayed, restrict local code execution to trusted accounts, and hunt for post-compromise indicators given the flaw's use as a 2015 APT28 zero-day and its documented use in ransomware chains per the CISA KEV entry.

CVE-2018-8120 is an elevation of privilege flaw in the Microsoft Windows Win32k kernel component, which fails to properly handle objects in memory. A local attacker who already has the ability to run code with low privileges on the machine must execute a specially crafted application that triggers the faulty object handling, allowing code to run in kernel mode. Successful exploitation yields elevated (SYSTEM-level) privileges and full control of the host, and it is commonly chained with a remote code execution or browser exploit, or used by malware — including ransomware — to deepen a compromise. Only systems running Windows 7, Windows Server 2008, or Windows Server 2008 R2 with unpatched Win32k are affected. The bug was exploited as a zero-day (reportedly by the ScarCruft APT group) before being fixed in May 2018 Patch Tuesday, a public PoC is available, and it was added to CISA's Known Exploited Vulnerabilities catalog in March 2022 with known ransomware use.

Do: Apply Microsoft's May 2018 security updates or later cumulative updates for Windows 7, Windows Server 2008, and Windows Server 2008 R2, prioritizing this KEV-listed flaw per the CISA required action. Systems beyond end of support that are not receiving Extended Security Updates should be migrated to a supported Windows version or isolated, since they remain permanently exposed to known APT and ransomware tooling. Review hosts for signs of local privilege escalation and ensure any RCE entry vector (browser, file format, or service exploit) is also patched, as this bug is typically used to escalate an initial foothold.

An elevation of privilege vulnerability exists in the Windows kernel's Win32k component, which fails to properly handle objects in memory (an uninitialized-variable condition). A local attacker who can already execute limited code on a target machine can trigger the flaw to gain kernel-level execution and elevate to SYSTEM privileges, giving full control of the host. Affected platforms are Windows 7, Windows 8.1, Windows RT 8.1, Windows 10 1507 and 1607, and Windows Server 2008, 2012 and 2016. The bug was patched in Microsoft's December 2019 Patch Tuesday after being actively exploited as a zero-day, including in the WizardOpium campaign attributed to a North Korea-linked actor. It is listed in CISA's Known Exploited Vulnerabilities catalog (added 2022-01-10, with known ransomware use) and carries a high EPSS of 74.3%.

Do: Apply the December 2019 security updates (or later cumulative updates) from Microsoft per CISA's required action. Because Windows 7/8.1 and Server 2008/2012 are past end of support and Server 2016 support is winding down, prioritize migration to supported Windows versions. Hunt for signs of local privilege escalation and follow-on activity, since this bug was used as a zero-day and appears in ransomware attack chains.

CVE-2020-0674 is a use-after-free memory corruption flaw (CWE-416) in the way the Internet Explorer scripting engine handles objects in memory, distinct from a series of sibling scripting-engine RCEs fixed at the same time (CVE-2020-0673, 0710, 0711, 0712, 0713, 0767). Triggering it requires user interaction: an attacker must convince a user to view a specially crafted web page (for example via a phishing link or malicious web content) while it renders in Internet Explorer, and the mishandled memory then allows code execution under the high-complexity, network-reachable conditions reflected in the CVSS vector (AV:N/AC:H/UI:R). Successful exploitation gives the attacker remote code execution with the privileges of the logged-in user, so the practical risk is highest for users browsing with Internet Explorer on Windows, including IE 8 through IE 11 targeted by the public exploits. Exploitation is confirmed in the wild: Microsoft warned of the flaw as an unpatched zero-day being used in targeted attacks before its February 2020 Patch Tuesday fix, public PoC/exploit code is available (including a working exploit for IE 8-11), the Magnitude exploit kit referenced in coverage used it as a delivery vector, and CISA added it to the Known Exploited Vulnerabilities catalog on 2021-11-03 alongside a very high EPSS score (86.9% probability of exploitation in 30 days, 100th percentile). The required remediation is to apply the Microsoft security updates from February 2020 that address this CVE.

Do: Apply the Microsoft February 2020 Patch Tuesday security updates that fix CVE-2020-0674 on all Windows endpoints and servers, prioritizing per the CISA KEV required action. Until patched, limit Internet Explorer use to trusted sites and consider Microsoft's suggested mitigations (such as restricting active scripting); note that third-party micropatches existed that emulated the vendor workaround without its usability side effects. After patching, verify IE11 remediation status across the estate and, where feasible, retire Internet Explorer usage entirely to reduce exposure to this recurring scripting-engine bug class.