Mozilla Firefox and Thunderbird Sandbox Escape
CVE-2019-11708 is a critical-severity improper input validation vulnerability in Firefox ESR from Mozilla, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 60.7.2 as the first without the flaw, so updating Firefox ESR to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on May 23, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Firefox ESR to 60.7.2 or a later version.
- Update Firefox to 67.0.4 or a later version.
- Update Thunderbird to 60.7.2 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on bugzilla.mozilla.org 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.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Mozilla | Firefox ESR | before 60.7.2 | 60.7.2 |
| Mozilla | Firefox | before 67.0.4 | 67.0.4 |
| Mozilla | Thunderbird | before 60.7.2 | 60.7.2 |
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
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:N/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 10.0 | Critical | NVD |
| CVSS 3.1 | 10.0 | Critical | CISA (ADP) |
| CVSS 2.0 | 10.0 | High | NVD |
Official description
Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxed parent process opening web content chosen by a compromised child process. When combined with additional vulnerabilities this could result in executing arbitrary code on the user's computer. This vulnerability affects Firefox ESR < 60.7.2, Firefox < 67.0.4, and Thunderbird < 60.7.2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How developers prevent this class of flaw
- Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
- Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
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
Advisories
Third-party and government advisories
- packetstormsecurity.com/files/155592/Mozilla-Firefox-Windows-64-Bit-Chain-Exploit.htmlThird Party Advisory, VDB Entry
- security.gentoo.org/glsa/201908-12Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-11708US Government Resource
Other vulnerabilities in Firefox ESR
- 9.8 Critical severity
- 8.8 High severity
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- 7.5 High severity
Recent Improper Input Validation vulnerabilities
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- 9.8 Critical severity
Drupal Core Remote Code Execution Exploited
- 8.6 High severity
- 8.6 High severity
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