CyberSecBulletin
CVE-2023-4408NVD status: Modified

BIND 9: Inefficient Algorithmic Complexity

Published Updated By the CyberSecBulletin desk

CVE-2023-4408 is a high-severity inefficient algorithmic complexity vulnerability in BIND 9 from ISC, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected BIND 9 versions: 9.0.0 through 9.16.45; 9.18.0 through 9.18.21; 9.19.0 through 9.19.19, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.39% chance of exploitation within 30 days, higher than 73% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of BIND 9 you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on kb.isc.org for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ISCBIND 99.0.0 through 9.16.45; 9.18.0 through 9.18.21; 9.19.0 through 9.19.19; 9.9.3-S1 through 9.11.37-S1; 9.16.8-S1 through 9.16.45-S1; 9.18.11-S1 through 9.18.21-S1Not stated
NetAppOntap9.14.1; 9.15.1Not stated
Fedora ProjectFedora38; 39Not stated
ISCBind9.0.0 through 9.16.45; 9.18.0 through 9.18.21; 9.19.0 through 9.19.19; 9.9.3; 9.16.8; 9.16.11; 9.16.12; 9.16.13; and 8 more rangesNot 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
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (isc.org).

Official description

The DNS message parsing code in `named` includes a section whose computational complexity is overly high. It does not cause problems for typical DNS traffic, but crafted queries and responses may cause excessive CPU load on the affected `named` instance by exploiting this flaw. This issue affects both authoritative servers and recursive resolvers. This issue affects BIND 9 versions 9.0.0 through 9.16.45, 9.18.0 through 9.18.21, 9.19.0 through 9.19.19, 9.9.3-S1 through 9.11.37-S1, 9.16.8-S1 through 9.16.45-S1, and 9.18.11-S1 through 9.18.21-S1.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Inefficient Algorithmic Complexity

An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

More Inefficient Algorithmic Complexity vulnerabilities (CWE-407)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in BIND 9

All BIND 9 vulnerabilities

Recent Inefficient Algorithmic Complexity vulnerabilities

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