Microsoft Warns of Unpatched IE Browser Zero
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2020-0674 | Use-After-Free RCE in Microsoft Internet Explorer Scripting Engine 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. | 7.5 | 87% | KEV PoC ×4 |
| masshundreds of millions of Windows endpoints (IE 11 was bundled with every supported Windows release at disclosure) |
Full article477 words · extracted from thehackernews.com · click to collapse
The Hacker NewsJan 18, 2020
Internet Explorer is dead, but not the mess it left behind.
Microsoft earlier today issued an emergency security advisory warning millions of Windows users of a new zero-day vulnerability in Internet Explorer (IE) browser that attackers are actively exploiting in the wild — and there is no patch yet available for it.
The vulnerability, tracked as CVE-2020-0674 and rated moderated, is a remote code execution issue that exists in the way the scripting engine handles objects in memory of Internet Explorer and triggers through JScript.dll library.
A remote attacker can execute arbitrary code on targeted computers and take full control over them just by convincing victims into opening a maliciously crafted web page on the vulnerable Microsoft browser.
"The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user," the advisory says.
"If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights."
Microsoft is aware of 'limited targeted attacks' in the wild and working on a fix, but until a patch is released, affected users have been provided with workarounds and mitigation to prevent their vulnerable systems from cyberattacks.
The affected web browsing software includes — Internet Explorer 9, Internet Explorer 10, and Internet Explorer 11 running on all versions of Windows 10, Windows 8.1, and the recently-discontinued Windows 7.
Workarounds: Defend Against Attacks Until A Patch Arrives
According to the advisory, preventing the loading of the JScript.dll library can manually block the exploitation of this vulnerability.
To restrict access to JScript.dll, run following commands on your Windows system with administrator privileges.
For 32-bit systems:
takeown / f% windir% \ system32 \ jscript.dll
cacls% windir% \ system32 \ jscript.dll / E / P everyone: N
For 64-bit systems:
takeown / f% windir% \ syswow64 \ jscript.dll
cacls% windir% \ syswow64 \ jscript.dll / E / P everyone: N
takeown / f% windir% \ system32 \ jscript.dll
cacls% windir% \ system32 \ jscript.dll / E / P everyone: N
When a patch update is available, users need to undo the workaround using the following commands:
For 32-bit systems:
cacls %windir%\system32\jscript.dll /E /R everyone
For 64-bit systems:
cacls %windir%\system32\jscript.dll /E /R everyone
cacls %windir%\syswow64\jscript.dll /E /R everyone
To be noted, some websites or features may break after disabling the vulnerable JScript.dll library that relies on this component, therefore, users should install updates as soon as they become available.
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Text extracted automatically; images, tables and formatting may be missing. Original: https://thehackernews.com/2020/01/internet-explorer-zero-day-attack.html