Ubiquiti EdgeRouter(s) and USG(s): Improper Control of Generation of Code
CVE-2023-23912 is a high-severity improper control of generation of code vulnerability in Ubiquiti EdgeRouter(s) and USG(s), with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.96% chance of exploitation within 30 days, higher than 62% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Usg Firmware to 4.4.57 or a later version.
- Update Usg-pro-4 Firmware to 4.4.57 or a later version.
- Update Er-10x Firmware to 2.0.9 or a later version.
- Read the advisory on community.ui.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Ubiquiti EdgeRouter(s) and USG(s) | Ubiquiti EdgeRouter(s) and USG(s) | Not specified in the record | Not stated |
| UI | Usg Firmware | before 4.4.57 | 4.4.57 |
| UI | Usg-pro-4 Firmware | before 4.4.57 | 4.4.57 |
| UI | Er-10x Firmware | before 2.0.9; 2.0.9 | 2.0.9 |
| UI | Er-12 Firmware | before 2.0.9; 2.0.9 | 2.0.9 |
| UI | Er-12p Firmware | before 2.0.9; 2.0.9 | 2.0.9 |
| UI | Er-4 Firmware | before 2.0.9; 2.0.9 | 2.0.9 |
| UI | Er-6p Firmware | before 2.0.9; 2.0.9 | 2.0.9 |
| UI | Er-8-xg Firmware | before 2.0.9; 2.0.9 | 2.0.9 |
| UI | Er-x Firmware | before 2.0.9; 2.0.9 | 2.0.9 |
| UI | Er-x-sfp Firmware | before 2.0.9; 2.0.9 | 2.0.9 |
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
- AdjacentThe attacker must be on the same local network segment.
- 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
- 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:A/AC:L/PR:N/UI:N/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) |
Official description
A vulnerability, found in EdgeRouters Version 2.0.9-hotfix.5 and earlier and UniFi Security Gateways (USG) Version 4.4.56 and earlier with their DHCPv6 prefix delegation set to dhcpv6-stateless or dhcpv6-stateful, allows a malicious actor directly connected to the WAN interface of an affected device to create a remote code execution vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Control of Generation of Code
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
How developers prevent this class of flaw
- Refactor your program so that you do not have to dynamically generate code.
- Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
More Improper Control of Generation of Code vulnerabilities (CWE-94)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Recent Improper Control of Generation of Code vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
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