CVE-2021-3761 OctoRPKI lacks contextual out-of-bounds check when validating RPKI ROA maxLength values

2021-09-0300:00:00

cloudflare

www.cve.org

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

7.7 High

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

34.7%

JSON

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.

CNA Affected

[
  {
    "product": "octorpki",
    "vendor": "Cloudflare",
    "versions": [
      {
        "lessThan": "1.3.0",
        "status": "affected",
        "version": "unspecified",
        "versionType": "custom"
      }
    ]
  }
]