BIG-IP: Use of Externally-Controlled Format String
CVE-2023-22374 is a high-severity use of externally-controlled format string vulnerability in BIG-IP from F5, with a CVSS 3.1 base score of 8.5 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, 16.1.3.4, 15.1.8.2 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 70.8% chance of exploitation within 30 days, which is in the top 0.59% of all scored CVEs.
Exploitation in the next 30 days is more likely than not, according to EPSS.
What to do
- Update BIG-IP to 17.1.0 or 16.1.3.4 or 15.1.8.2 or 14.1.5.4, whichever matches your release line, or a later version.
- Read the advisory on my.f5.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| F5 | BIG-IP | 17.0.0 up to, but not including, 17.1.0; 16.1.2.2 up to, but not including, 16.1.3.4; 15.1.5.1 up to, but not including, 15.1.8.2; 14.1.4.6 up to, but not including, 14.1.5.4; 13.1.5 and later | 17.1.0, 16.1.3.4, 15.1.8.2, 14.1.5.4 |
| F5 | Big-ip Access Policy Manager | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
| F5 | Big-ip Advanced Firewall Manager | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
| F5 | Big-ip Analytics | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
| F5 | Big-ip Application Acceleration Manager | 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
| F5 | Big-ip Application Security Manager | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.0; 17.0.0 | Not stated |
| F5 | Big-ip Ddos Hybrid Defender | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5 | Not stated |
| F5 | Big-ip Domain Name System | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 17.0.0 | Not stated |
| F5 | Big-ip Fraud Protection Service | 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
| F5 | Big-ip Link Controller | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
| F5 | Big-ip Local Traffic Manager | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
| F5 | Big-ip Policy Enforcement Manager | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
| F5 | Big-ip SSL Orchestrator | 14.1.4.6 through 14.1.5; 15.1.5.1 through 15.1.8; 16.1.2.2 through 16.1.3; 13.1.5; 17.0.0 | Not stated |
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
- 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:H/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.5 | High | CNA (f5.com) |
| CVSS 3.1 | 8.5 | High | NVD |
Official description
A format string vulnerability exists in iControl SOAP that allows an authenticated attacker to crash the iControl SOAP CGI process or, potentially execute arbitrary code. In appliance mode BIG-IP, a successful exploit of this vulnerability 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: Use of Externally-Controlled Format String
The product uses a function that accepts a format string as an argument, but the format string originates from an external source.
How developers prevent this class of flaw
- Choose a language that is not subject to this flaw.
- Ensure that all format string functions are passed a static string which cannot be controlled by the user, and that the proper number of arguments are always sent to that function as well. If at all possible, use functions that do not support the %n operator in format strings.
- Run compilers and linkers with high warning levels, since they may detect incorrect usage.
More Use of Externally-Controlled Format String vulnerabilities (CWE-134)
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
Other vulnerabilities in BIG-IP
- 9.8 Critical severity
F5 BIG-IP APM Heap-based Buffer Overflow Exploited
- 8.8 High severity
- 7.5 High severity
- 8.7 High severity
- 8.7 High severity
- 7.5 High severity
Recent Use of Externally-Controlled Format String vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
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