BIND 9: Out-of-bounds Write
CVE-2023-2911 is a high-severity out-of-bounds write 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: 9.16.33 through 9.16.41; 9.18.7 through 9.18.15; 9.16.33-S1 through 9.16.41-S1, 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 2.43% chance of exploitation within 30 days, higher than 85% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of BIND 9 you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on kb.isc.org for workarounds and exact fixed builds.
- 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 |
|---|---|---|---|
| ISC | BIND 9 | 9.16.33 through 9.16.41; 9.18.7 through 9.18.15; 9.16.33-S1 through 9.16.41-S1; 9.18.11-S1 through 9.18.15-S1 | Not stated |
| ISC | Bind | 9.16.33 through 9.16.41; 9.18.7 through 9.18.15; 9.18.11 through 9.18.15 | Not stated |
| Debian | Debian Linux | 11.0; 12.0 | Not stated |
| Fedora Project | Fedora | 37; 38 | Not stated |
| NetApp | Active Iq Unified Manager | Not specified in the record | Not stated |
| NetApp | H700s Firmware | Not specified in the record | Not stated |
| NetApp | H300s Firmware | Not specified in the record | Not stated |
| NetApp | H410c Firmware | Not specified in the record | Not stated |
| NetApp | H410s Firmware | Not specified in the record | Not stated |
| NetApp | H500s Firmware | Not specified in the record | 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 CNA (isc.org).
Official description
If the `recursive-clients` quota is reached on a BIND 9 resolver configured with both `stale-answer-enable yes;` and `stale-answer-client-timeout 0;`, a sequence of serve-stale-related lookups could cause `named` to loop and terminate unexpectedly due to a stack overflow. This issue affects BIND 9 versions 9.16.33 through 9.16.41, 9.18.7 through 9.18.15, 9.16.33-S1 through 9.16.41-S1, and 9.18.11-S1 through 9.18.15-S1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
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
Advisories
Patches and release notes
- openwall.com/lists/oss-security/2023/06/21/6Mailing List, Third Party Advisory
Third-party and government advisories
- lists.fedoraproject.org/archives/list/[email protected]/message/SEFCEVCTYEMKTWA7V7EYPI…Mailing List, Third Party Advisory
- lists.fedoraproject.org/archives/list/[email protected]/message/U3K6AJK7RRSR53HRF5GGKP…Mailing List, Third Party Advisory
- security.netapp.com/advisory/ntap-20230703-0010/Third Party Advisory
- debian.org/security/2023/dsa-5439Third Party Advisory
Other vulnerabilities in BIND 9
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Out-of-bounds Write vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
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