Microsoft Internet Explorer Scripting Engine Memory Corruption
CVE-2019-1429 is a high-severity use after free vulnerability in Internet Explorer 9 from Microsoft, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected Internet Explorer 9 versions: Windows Server 2008 for 32-bit Systems Service Pack 2; Windows Server 2008 for x64-based Systems Service Pack 2. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of Internet Explorer 9 you run against the affected versions below, and install the vendor's latest release.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on portal.msrc.microsoft.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Internet Explorer 9 | Windows Server 2008 for 32-bit Systems Service Pack 2; Windows Server 2008 for x64-based Systems Service Pack 2 | Not stated |
| Microsoft | Internet Explorer 11 | Windows 7 for 32-bit Systems Service Pack 1; Windows 7 for x64-based Systems Service Pack 1; Windows Server 2008 R2 for x64-based Systems Service Pack 1; Windows 8.1 for 32-bit systems; Windows 8.1 for x64-based systems; Windows Server 2012 R2; Windows RT 8.1; Windows 10 for 32-bit Systems; and 14 more ranges | Not stated |
| Microsoft | Internet Explorer 11 on Windows Server 2012 | Not specified in the record | Not stated |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1903 for 32-bit Systems | Not specified in the record | Not stated |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1903 for x64-based Systems | Not specified in the record | Not stated |
| Microsoft | Internet Explorer 11 on Windows 10 Version 1903 for ARM64-based Systems | Not specified in the record | Not stated |
| Microsoft | Internet Explorer 10 | Windows Server 2012 | Not stated |
| Microsoft | Internet Explorer | 9; 10; 11 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 3.1 | 7.5 | High | CISA (ADP) |
| CVSS 2.0 | 7.6 | High | NVD |
Official description
A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka 'Scripting Engine Memory Corruption Vulnerability'. This CVE ID is unique from CVE-2019-1426, CVE-2019-1427, CVE-2019-1428.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-1429US Government Resource
Technical write-ups (may include proof of concept)
- packetstormsecurity.com/files/155433/Microsoft-Internet-Explorer-Use-After-Free.htmlExploit, Third Party Advisory, VDB Entry
Other vulnerabilities in Internet Explorer 9
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
Microsoft MSHTML Remote Code Execution Exploited
Recent Use After Free vulnerabilities
- 7.8 High severity
Android Kernel Use-After-Free Exploited
- 6.5 Medium severity
Google Chrome Blink Use-After-Free Exploited
- 9.8 Critical severity
- 7.8 High severity
Apache HTTP Server Privilege Escalation Exploited
- 7.8 High severity
Adobe Flash Player Use-After-Free Exploited
- 7.5 High severity
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