BIG-IP APM: Improper Limitation of a Pathname to a Restricted Directory
CVE-2022-31473 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in BIG-IP APM from F5, with a CVSS 3.1 base score of 7.7 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 15.1.4, 16.1.1 as the first without the flaw, so updating BIG-IP APM to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.08% chance of exploitation within 30 days, higher than 82% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update BIG-IP APM to 15.1.4 or 16.1.1, whichever matches your release line, or a later version.
- Update Big-ip Access Policy Manager to 15.1.4 or a later version.
- Read the advisory on support.f5.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| F5 | BIG-IP APM | 15.1.x up to, but not including, 15.1.4; 16.1.x up to, but not including, 16.1.1 | 15.1.4, 16.1.1 |
| F5 | Big-ip Access Policy Manager | 15.1.0 up to, but not including, 15.1.4; 16.1.0 | 15.1.4 |
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
- LowA basic user account is enough.
- 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
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.8 | Medium | CNA (f5.com) |
| CVSS 3.1 | 7.7 | High | NVD |
Official description
In BIG-IP Versions 16.1.x before 16.1.1 and 15.1.x before 15.1.4, when running in Appliance mode, an authenticated attacker may be able to bypass Appliance mode restrictions due to a directory traversal vulnerability in an undisclosed page within iApps. A successful exploit can allow the attacker to cross a security boundary. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- 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.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in BIG-IP APM
- 7.5 High severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 7.2 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.2 High severity
- 7.2 High severity
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