CyberSecBulletin
CVE-2023-41373NVD status: Modified

BIG-IP: Improper Limitation of a Pathname to a Restricted Directory

Published Updated By the CyberSecBulletin desk

CVE-2023-41373 is a critical-severity improper limitation of a pathname to a restricted directory vulnerability in BIG-IP from F5, with a CVSS 3.1 base score of 9.9 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 17.1.0.3, 16.1.4.1, 15.1.10.2 as the first without the flaw, so updating BIG-IP to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.29% chance of exploitation within 30 days, higher than 84% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update BIG-IP to 17.1.0.3 or 16.1.4.1 or 15.1.10.2 or 14.1.5.6, whichever matches your release line, or a later version.
  2. Update Big-ip Access Policy Manager to 14.1.5.6 or 15.1.10.2 or 16.1.4.1 or 17.1.0.3, whichever matches your release line, or a later version.
  3. Update Big-ip Advanced Firewall Manager to 14.1.5.6 or 15.1.10.2 or 16.1.4.1 or 17.1.0.3, whichever matches your release line, or a later version.
  4. Read the advisory on my.f5.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
F5BIG-IP17.1.0 up to, but not including, 17.1.0.3; 16.1.0 up to, but not including, 16.1.4.1; 15.1.0 up to, but not including, 15.1.10.2; 14.1.0 up to, but not including, 14.1.5.6; 13.1.0 and later17.1.0.3, 16.1.4.1, 15.1.10.2, 14.1.5.6
F5Big-ip Access Policy Manager13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Advanced Firewall Manager13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Application Security Manager13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Domain Name System13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Local Traffic Manager13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Advanced Web Application Firewall13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Analytics13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Application Acceleration Manager13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Application Visibility And Reporting13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Carrier-grade Nat13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Ddos Hybrid Defender13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Fraud Protection Service13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Global Traffic Manager13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Link Controller13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Policy Enforcement Manager13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip SSL Orchestrator13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Webaccelerator13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3
F5Big-ip Websafe13.1.0 through 13.1.5; 14.1.0 up to, but not including, 14.1.5.6; 15.1.0 up to, but not including, 15.1.10.2; 16.1.0 up to, but not including, 16.1.4.1; 17.1.0 up to, but not including, 17.1.0.314.1.5.6, 15.1.10.2, 16.1.4.1, 17.1.0.3

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
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:L/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (f5.com).

Official description

A directory traversal vulnerability exists in the BIG-IP Configuration Utility that may allow an authenticated attacker to execute commands on the BIG-IP system. For BIG-IP system running in Appliance mode, 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

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in BIG-IP

All BIG-IP vulnerabilities

Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities

Spotted an error? Tell us.