CVE-2024-38178
Microsoft Windows Scripting Engine Memory Corruption Vulnerability
Description
CVE-2024-38178 is a high-severity memory corruption vulnerability in the Windows Scripting Engine with a CVSS v3.1 base score of 7.5. The flaw allows a remote attacker to execute arbitrary code on a victim's system by exploiting a memory corruption issue in the scripting engine, though exploitation requires high attack complexity and user interaction. CISA has added CVE-2024-38178 to the Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of September 3, 2024, and the ransomware association is classified as unknown. With an EPSS score of 26.85% at the 96.2nd percentile, the vulnerability is under significant active exploitation. It affects Windows 10, Windows 11, and Windows Server 2012 R2 through Server 2022 23H2.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | windows 10 1507 | < 10.0.10240.20751 |
| microsoft | windows 10 1607 | < 10.0.14393.7259 |
| microsoft | windows 10 1809 | < 10.0.17763.6189 |
| microsoft | windows 10 21h2 | < 10.0.19044.4780 |
| microsoft | windows 10 22h2 | < 10.0.19045.4780 |
| microsoft | windows 11 21h2 | < 10.0.22000.3147 |
| microsoft | windows 11 22h2 | < 10.0.22621.4037 |
| microsoft | windows 11 23h2 | < 10.0.22631.4037 |
| microsoft | windows 11 24h2 | < 10.0.26100.1457 |
| microsoft | windows server 2012 | r2 |
| microsoft | windows server 2016 | < 10.0.14393.7259 |
| microsoft | windows server 2019 | < 10.0.17763.6189 |
| microsoft | windows server 2022 | < 10.0.20348.2655 |
| microsoft | windows server 2022 23h2 | < 10.0.25398.1085 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-38178(Patch, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-38178(US Government Resource)
Weakness Type
Scripting Engine Memory Corruption
CVE-2024-38178 is a memory corruption vulnerability in the Windows Scripting Engine, the component responsible for interpreting and executing scripts (such as JScript) within the Windows operating system. Memory corruption in scripting engines typically involves type confusion, use-after-free, or heap buffer overflow conditions that occur during the parsing or execution of crafted script content. When the scripting engine processes specially crafted script code, it can enter an inconsistent state where memory pointers reference incorrect object types or freed memory regions. An attacker who can trigger this condition can redirect script engine execution to run arbitrary code with the privileges of the user running the script host process. Scripting engine vulnerabilities are frequently targeted by advanced persistent threat (APT) groups because they can be triggered through web browsing or document rendering.
Impact Analysis
The business impact of CVE-2024-38178 spans all three security dimensions with high severity. Confidentiality is fully compromised (C:H) because successful exploitation grants the attacker code execution in the context of the current user, which can be leveraged to steal credentials, exfiltrate sensitive documents, access browser saved passwords, and capture keystrokes.
Integrity faces maximum impact (I:H) as the attacker can install malware, modify system files, tamper with security configurations, and establish persistent access through scheduled tasks, registry modifications, or startup entries.
Availability is fully at risk (A:H) because arbitrary code execution enables the attacker to disrupt operations through ransomware, system destruction, or resource exhaustion attacks. The network attack vector (AV:N) means the exploit can be delivered remotely through malicious web pages or embedded content. However, the high attack complexity (AC:H) indicates that exploitation depends on specific conditions being met, and user interaction (UI:R) requires the victim to visit a malicious page or open crafted content. The EPSS score of 26.85% at the 96.2nd percentile confirms that despite these conditions, sophisticated threat actors are successfully exploiting this vulnerability at scale.
Exploit Maturity
CVE-2024-38178 has confirmed active exploitation, as demonstrated by its inclusion in CISA's Known Exploited Vulnerabilities catalog with a remediation deadline of September 3, 2024. The EPSS score of 26.85% at the 96.2nd percentile indicates very significant exploitation activity despite the high attack complexity requirement.
Microsoft has confirmed exploitation in the wild through its security advisory. Scripting engine memory corruption vulnerabilities are traditionally favored by APT groups and state-sponsored actors for targeted attacks, as they enable remote code execution through web browsing with minimal indicators visible to the victim. The high attack complexity (AC:H) suggests the exploitation technique may require the target to have Internet Explorer mode enabled in Microsoft Edge or use a specific scripting engine configuration. The ransomware association is classified as unknown, but the remote code execution capability makes it a viable initial access vector for any attack objective including ransomware deployment.
Remediation
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Apply the August 2024 Microsoft security updates immediately. Install the cumulative update from the Microsoft Security Response Center advisory. Ensure all affected systems are updated, including Windows 10 (all supported versions), Windows 11 (21H2 through 24H2), and Windows Server 2012 R2 through Server 2022 23H2.
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Disable Internet Explorer mode in Microsoft Edge where not required. The scripting engine vulnerability is associated with legacy JScript processing, which is most commonly triggered when Internet Explorer mode is active. Review enterprise browser policies and disable IE mode for users and sites that do not require it, reducing the attack surface for this class of vulnerability.
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Deploy network-level protections against malicious web content. Configure web proxies and secure web gateways to block access to known malicious domains and URLs associated with scripting engine exploitation. Enable URL filtering categories that block newly registered domains and uncategorized sites frequently used in watering-hole attacks.
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Enable Enhanced Security Configuration on servers. For Windows Server systems, ensure Internet Explorer Enhanced Security Configuration (IE ESC) is enabled, which restricts the scripting engine's execution capabilities and significantly reduces the exploitable attack surface on server operating systems.
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Implement browser isolation for high-risk users. Deploy browser isolation solutions for users who handle sensitive data or have elevated privileges. Browser isolation prevents scripting engine exploits from executing in the context of the user's actual workstation, containing the impact within a disposable virtual environment.
Technical Details
CVE-2024-38178 carries a CVSS v3.1 vector of CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H, resulting in a high base score of 7.5. The network attack vector (AV:N) means the exploit is delivered remotely, typically through crafted web content. The high attack complexity (AC:H) indicates that specific preconditions must be met for successful exploitation, such as the target having Internet Explorer mode enabled or using a specific scripting host configuration. No privileges (PR:N) are required, but user interaction (UI:R) is necessary, meaning the victim must navigate to a malicious page or open crafted content.
The vulnerability is a memory corruption issue in the Windows Scripting Engine (jscript9.dll or related components). During the processing of specially crafted script content, the engine fails to properly manage memory object lifetimes or type information, leading to a condition where the engine operates on memory that has been freed, reallocated, or misidentified. This creates a memory corruption primitive that an attacker can exploit using techniques such as heap spraying to place controlled data at predictable memory addresses, followed by redirecting execution to shellcode or a ROP (Return-Oriented Programming) chain. The scope is unchanged (S:U), and all three impact metrics are high, reflecting full compromise of the executing context upon successful exploitation. Affected versions span Windows 10 1507 through 22H2, Windows 11 21H2 through 24H2, Windows Server 2012 R2, and Windows Server 2016 through 2022 23H2.
Frequently Asked Questions
What is CVE-2024-38178?
CVE-2024-38178 is a high-severity memory corruption vulnerability in the Windows Scripting Engine that enables remote code execution when a user visits a malicious web page or opens crafted content. It carries a CVSS v3.1 score of 7.5 and is actively exploited in the wild.
Does CVE-2024-38178 require Internet Explorer?
The high attack complexity (AC:H) suggests the vulnerability requires specific conditions such as Internet Explorer mode being enabled in Microsoft Edge. While the exact conditions may vary, disabling IE mode where not required significantly reduces the attack surface.
Can CVE-2024-38178 be exploited without user interaction?
No, CVE-2024-38178 requires user interaction (UI:R). The victim must visit a malicious web page or open content that triggers the scripting engine vulnerability. This makes it a common vector for targeted phishing and watering-hole attacks.
Which organizations should prioritize patching CVE-2024-38178?
All organizations running affected Windows versions should prioritize this patch, but those with Internet Explorer mode enabled, legacy web application dependencies, or users who regularly browse external websites are at highest risk. The EPSS score of 26.85% at the 96.2nd percentile confirms widespread exploitation.
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