Microsoft Internet Explorer Use-After-Free
CVE-2012-4792 is a high-severity use after free vulnerability in ie from Microsoft, with a CVSS 3.1 base score of 8.8 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 ie versions: 6.0 through 8.0. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on July 23, 2024, 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 ie you run against the affected versions below, and install the vendor's latest release.
- CISA's required action: The impacted product is end-of-life and should be disconnected if still in use.
- Read the advisory on technet.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 | ie | 6.0 through 8.0 | Not stated |
| Microsoft | Internet Explorer | 6; 7; 8 | 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
- LowNo special conditions are needed; the attack works reliably.
- 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:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
| CVSS 2.0 | 9.3 | High | NVD |
Official description
Use-after-free vulnerability in Microsoft Internet Explorer 6 through 8 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to an object that (1) was not properly allocated or (2) is deleted, as demonstrated by a CDwnBindInfo object, and exploited in the wild in December 2012.
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.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- eromang.zataz.com/2012/12/29/attack-and-ie-0day-informations-used-against-council-on-foreign-relations/Third Party Advisory
- packetstormsecurity.com/files/119168/Microsoft-Internet-Explorer-CDwnBindInfo-Object-Use-After-Free.htmlThird Party Advisory, VDB Entry
- kb.cert.org/vuls/id/154201Third Party Advisory, US Government Resource
- us-cert.gov/cas/techalerts/TA13-008A.htmlThird Party Advisory, US Government Resource
- us-cert.gov/cas/techalerts/TA13-015A.htmlThird Party Advisory, US Government Resource
- github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/browser/ie_cbutton_uaf.rbThird Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2012-4792US Government Resource
Recent Use After Free vulnerabilities
- 8.1 High severity
- 9.3 High severity
- 8.8 High severity
- 7.8 High severity
Adobe Acrobat and Reader Use-After-Free Exploited
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