Sophos Firewall: Reliance on Untrusted Inputs in a Security Decision
CVE-2024-13974 is a high-severity reliance on untrusted inputs in a security decision vulnerability in Sophos Firewall from Sophos, with a CVSS 3.1 base score of 8.1 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 21.0 MR1 (21.0.1) as the first without the flaw, so updating Sophos Firewall to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 9.07% chance of exploitation within 30 days, which is in the top 4.63% of all scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Sophos Firewall to 21.0 MR1 (21.0.1) or a later version.
- Update Firewall Firmware to 21.0.1 or a later version.
- Read the advisory on sophos.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.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Sophos | Sophos Firewall | before 21.0 MR1 (21.0.1) | 21.0 MR1 (21.0.1) |
| Sophos | Firewall Firmware | before 21.0.1 | 21.0.1 |
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
- 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:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (sophos.com).
Official description
A business logic vulnerability in the Up2Date component of Sophos Firewall older than version 21.0 MR1 (20.0.1) can lead to attackers controlling the firewall’s DNS environment to achieve remote code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reliance on Untrusted Inputs in a Security Decision
The product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. With a stateless protocol such as HTTP, use a framework that maintains the state for you. Examples include ASP.NET View State and the OWASP ESAPI Session Management feature. Be careful of language features that provide state support, since these might be provided as a convenience to the programmer and may not be considering security.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
More Reliance on Untrusted Inputs in a Security Decision vulnerabilities (CWE-807)
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
Other vulnerabilities in Sophos Firewall
- 9.8 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 7.2 High severity
- 8.8 High severity
- 9.8 Critical severity
Recent Reliance on Untrusted Inputs in a Security Decision vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 7.1 High severity
- 7.2 High severity
- 7.5 High severity
- 8.1 High severity
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