Attacker Value
High
(2 users assessed)
Exploitability
Very High
(2 users assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Network
1

CVE-2020-8616: NXNSAttack: Recursive DNS Inefficiencies and Vulnerabilities

Disclosure Date: May 19, 2020
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

A malicious actor who intentionally exploits this lack of effective limitation on the number of fetches performed when processing referrals can, through the use of specially crafted referrals, cause a recursing server to issue a very large number of fetches in an attempt to process the referral. This has at least two potential effects: The performance of the recursing server can potentially be degraded by the additional work required to perform these fetches, and The attacker can exploit this behavior to use the recursing server as a reflector in a reflection attack with a high amplification factor.

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2
Ratings
Technical Analysis

This isn’t going to be useful to a pen tester other than a report note, so don’t expect this to get a lot of interest to anyone who is trying to not get noticed. This will be useful I think as a nation-state level attack or in ransom-ware type scenarios, but there are plenty of other DoS techniques out there as well.

CVSS V3 Severity and Metrics
Base Score:
8.6 High
Impact Score:
4
Exploitability Score:
3.9
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Changed
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Vendors

  • ISC

Products

  • BIND9

References

Advisory

Additional Info

Technical Analysis