CVE-2021-23047
Published: 14 September 2021
Summary
CVE-2021-23047 is a medium-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in F5 Big-Ip Access Policy Manager. Its CVSS base score is 5.3 (Medium).
Operationally, ranked in the top 43.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-10165
Vulnerability details
On version 16.x before 16.1.0, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.3, and all versions of 13.1.x, 12.1.x and 11.6.x, when BIG-IP APM performs Online Certificate Status Protocol (OCSP) verification of a certificate that contains Authority Information Access (AIA), undisclosed requests…
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may cause an increase in memory use. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.
Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.
Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.
The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.
Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.