Google Warns of Internet Explorer Zero-Day Vulnerability Exploited by ScarCruft Hackers
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2020-1380 | Memory Corruption RCE in Microsoft Internet Explorer Scripting Engine CVE-2020-1380 is a memory corruption vulnerability (an out-of-bounds write, CWE-787) in the Microsoft Internet Explorer scripting engine that can corrupt memory when the engine processes maliciously crafted script content. It is triggered by luring a user to visit an attacker-controlled or compromised web page in Internet Explorer or in an application that invokes the IE engine, with no authentication required. Successful exploitation allows the attacker to execute arbitrary code in the context of the current user, gaining that user's privileges on the system. All installations of the affected Microsoft Internet Explorer versions are potentially exposed, with the greatest risk to legacy and enterprise Windows systems that still browse or render content with IE. The flaw is on CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating exploitation in the wild, while no public proof-of-concept is known and ransomware use is unconfirmed. Do: Apply Microsoft's June 2020 (or later) Windows cumulative security updates on every system running Internet Explorer, per the vendor instructions cited by CISA. Given the KEV listing (added 2021-11-03) and high EPSS (~24% 30-day exploitation probability, 98th percentile), treat this as a priority patch. Reduce attack surface by steering users to Microsoft Edge instead of IE for web browsing and auditing internal apps or legacy sites that still invoke the IE engine to render external content. | 7.8 | 24% | KEV |
| masshundreds of millions of Windows devices historically able to run Internet Explorer; exact currently-vulnerable count unknown | |
| CVE-2021-26411 | Use-After-Free Memory Corruption in Microsoft Internet Explorer Exploited in the Wild CVE-2021-26411 is a use-after-free (CWE-416) memory corruption vulnerability in Microsoft Internet Explorer's web rendering engine that can lead to remote code execution. It is triggered when a user, typically lured via a link, email, or watering-hole page, views attacker-controlled web content that corrupts memory, consistent with the CVSS profile requiring network access and user interaction. A successful attacker gains code execution in the context of the logged-on user, which in observed campaigns was chained into malware delivery (including exploit-kit payloads such as Dridex and VBA-based malware). Any Windows system that renders web content with Internet Explorer or its IE/MSHTML components (Edge is also listed among affected CPE products) is potentially affected, though specific version ranges are not provided in the source data. The flaw was exploited as a zero-day around Microsoft's March 2021 Patch Tuesday, was added to CISA KEV on 2021-11-03 with known ransomware use, and carries an 80.8% EPSS probability of exploitation within 30 days. Do: Apply Microsoft's March 2021 cumulative security updates for Internet Explorer, or any later cumulative update, across all Windows clients and servers, prioritizing user workstations per the CISA KEV required action. Review proxy and endpoint logs for visits to compromised watering-hole sites (notably Korean-language news sites) and for follow-on malware such as Dridex, and restrict or disable IE/legacy IE-mode rendering of untrusted web content where feasible. | 8.8 | 81% | KEV ransomware |
| mass≈hundreds of millions of Windows endpoints (IE/MSHTML components are present on effectively all supported Windows clients and servers) | |
| CVE-2022-41128 | Out-of-bounds Write RCE in Microsoft Windows JScript9 Scripting Engine CVE-2022-41128 is a remote code execution flaw in the JScript9 scripting language on Microsoft Windows, classed by the CWE taxonomy as an out-of-bounds write (CWE-787), meaning crafted input can write past the end of an allocated memory buffer. Microsoft's description is limited, but flaws of this type in scripting engines are typically triggered when the engine processes attacker-crafted script content, such as script embedded in a web page or document. Successful exploitation would let an attacker execute arbitrary code in the context of the affected process on the target Windows system. Any Windows deployment that processes content through the JScript9 engine is affected, which spans a broad share of the Windows installed base. The flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2022-11-08, indicating confirmed in-the-wild exploitation; no public proof-of-concept is known, EPSS puts the 30-day exploitation probability at 24.6% (98th percentile), and ransomware use is unknown. Do: Apply Microsoft's Windows security updates per vendor instructions without delay, prioritizing internet-facing and user-workstation systems because the flaw is KEV-listed as actively exploited. Until patched, limit exposure to untrusted script-bearing web content and documents from unverified sources, and verify remediation status against Microsoft's update guidance. | 8.8 | 25% | KEV |
| mass≈1 billion+ Windows devices (order of magnitude; the engine ships with Windows itself) |
Full article461 words · extracted from thehackernews.com · click to collapse
Ravie LakshmananDec 08, 2022Patch Management / Zero-Day
An Internet Explorer zero-day vulnerability was actively exploited by a North Korean threat actor to target South Korean users by capitalizing on the recent Itaewon Halloween crowd crush to trick users into downloading malware.
The discovery, reported by Google Threat Analysis Group researchers Benoît Sevens and Clément Lecigne, is the latest set of attacks perpetrated by ScarCruft, which is also called APT37, InkySquid, Reaper, and Ricochet Chollima.
"The group has historically focused their targeting on South Korean users, North Korean defectors, policy makers, journalists, and human rights activists," TAG said in a Thursday analysis.
The new findings illustrate the threat actor's continued abuse of Internet Explorer flaws such as CVE-2020-1380 and CVE-2021-26411 to drop backdoors like BLUELIGHT and Dolphin, the latter of which was disclosed by Slovak cybersecurity firm ESET late last month.
Another key tool in its arsenal is RokRat, a Windows-based remote access trojan that comes with a wide range of functions that allow it to capture screenshots, log keystrokes, and even harvest Bluetooth device information.
The attack chain observed by Google TAG entails the use of a malicious Microsoft Word document that was uploaded to VirusTotal on October 31, 2022. It abuses yet another Internet Explorer zero-day flaw in the JScript9 JavaScript engine, CVE-2022-41128, that was patched by Microsoft last month.
The file references the October 29 incident that took place in the Itaewon neighborhood of Seoul and exploits public interest in the tragedy to retrieve an exploit for the vulnerability upon opening it. The attack is enabled by the fact that Office renders HTML content using Internet Explorer.
As the MalwareHunterTeam points out, the same Word file was previously shared by the Shadow Chaser Group on October 31, 2022, describing it as an "interesting DOCX injection template sample" that originated from Korea.
Successful exploitation is followed by the delivery of a shellcode that wipes all traces by clearing the Internet Explorer cache and history as well as downloading the next stage payload.
Google TAG said it could not recover the follow-on malware used in the campaign, although it's suspected to have involved the deployment of RokRat, BLUELIGHT, or Dolphin.
"It is not surprising that they continue to target South Korean users," ESET malware analyst Filip Jurčacko told The Hacker News. "We haven't seen ScarCruft use zero-day exploits for some time. Previously, they were repurposing public PoCs of n-day exploits."
"Given the rarity/scarcity of zero-day exploits, we expect ScarCruft would use it in combination with some of their more sophisticated backdoors such as Dolphin. Moreover, the office theme of [command-and-control] domains matches previous campaigns."
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