CVE-2021-3761

OctoRPKI lacks contextual out-of-bounds check when validating RPKI ROA maxLength values

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

Any CA issuer in the RPKI can trick OctoRPKI prior to 1.3.0 into emitting an invalid VRP "MaxLength" value, causing RTR sessions to terminate. An attacker can use this to disable RPKI Origin Validation in a victim network (for example AS 13335 - Cloudflare) prior to launching a BGP hijack which during normal operations would be rejected as "RPKI invalid". Additionally, in certain deployments RTR session flapping in and of itself also could cause BGP routing churn, causing availability issues.

Cualquier emisor de CA en la RPKI puede engañar a OctoRPKI anterior a versión 1.3.0 para que emita un valor "MaxLength" de VRP no válido, causando la terminación de las sesiones RTR. Un atacante puede usar esto para deshabilitar la Comprobación de Origen RPKI en una red víctima (por ejemplo AS 13335 - Cloudflare) antes de lanzar un hijack BGP que durante las operaciones normales sería rechazado como "RPKI invalid". Además, en determinados despliegues, la ruptura de la sesión de RTR también podría causar por sí misma la ruptura del enrutamiento BGP, causando problemas de disponibilidad

*Credits: Job Snijders

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-09-01 CVE Reserved
2021-09-09 CVE Published
2024-07-12 EPSS Updated
2024-09-17 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-787: Out-of-bounds Write

CAPEC

References (2)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://github.com/cloudflare/cfrpki/security/advisories/GHSA-c8xp-8mf3-62h9	2022-04-04

URL	Date	SRC
https://www.debian.org/security/2022/dsa-5041	2022-04-04

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Cloudflare Search vendor "Cloudflare"		Octorpki Search vendor "Cloudflare" for product "Octorpki"				< 1.3.0 Search vendor "Cloudflare" for product "Octorpki" and version " < 1.3.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				11.0 Search vendor "Debian" for product "Debian Linux" and version "11.0"		-		Affected