dns_server: Insufficient Control of Network Message Volume (Network Amplification)
CVE-2023-49203 is a high-severity insufficient control of network message volume (network amplification) vulnerability in dns_server from Technitium, 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 dns_server versions: 11.5.3. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.65% chance of exploitation within 30 days, higher than 52% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of dns_server you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Technitium | dns_server | 11.5.3 | Not stated |
| Technitium | Dnsserver | 11.5.3 | Not 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 CISA (ADP).
Official description
Technitium 11.5.3 allows remote attackers to cause a denial of service (bandwidth amplification) because the DNSBomb manipulation causes accumulation of low-rate DNS queries such that there is a large-sized response in a burst of traffic.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Insufficient Control of Network Message Volume (Network Amplification)
The product does not sufficiently monitor or control transmitted network traffic volume, so that an actor can cause the product to transmit more traffic than should be allowed for that actor.
How developers prevent this class of flaw
- An application must make network resources available to a client commensurate with the client's access level.
- Define a clear policy for network resource allocation and consumption.
- An application must, at all times, keep track of network resources and meter their usage appropriately.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
- technitium.com/dns/Product
Other vulnerabilities in dns_server
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
Recent Insufficient Control of Network Message Volume (Network Amplification) vulnerabilities
- 7.5 High severity
- 8.6 High severity
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