PatchSiren cyber security CVE debrief

CVE-2023-4408 ISC CVE debrief

CVE-2023-4408 is a HIGH severity vulnerability (CVSS 7.5) in BIND 9 DNS message parsing code that can cause excessive CPU load through crafted queries and responses. The flaw affects both authoritative servers and recursive resolvers. While this is fundamentally a BIND 9 issue, Siemens SINEC INS is affected as it incorporates vulnerable BIND 9 components. The vulnerability was published on November 12, 2024, with coordinated disclosure through CISA and Siemens security advisories.

Vendor: ISC
Product: SINEC INS
CVSS: HIGH 7.5
CISA KEV: Not listed in stored evidence
Original CVE published: 2024-11-12
Original CVE updated: 2024-11-12
Advisory published: 2024-11-12
Advisory updated: 2024-11-12

Who should care

Organizations operating Siemens SINEC INS for industrial network management, DNS infrastructure administrators running affected BIND 9 versions, OT security teams responsible for critical infrastructure DNS services, and security operations centers monitoring for denial-of-service conditions in DNS infrastructure.

Technical summary

The DNS message parsing implementation in BIND 9 `named` contains a code path with excessive computational complexity. This vulnerability can be triggered by crafted DNS queries or responses, causing CPU resource exhaustion. The issue affects both authoritative and recursive DNS server modes. Normal DNS traffic patterns do not trigger the vulnerability, making it a targeted attack vector rather than an incidental reliability issue.

Defensive priority

HIGH

Recommended defensive actions

Update Siemens SINEC INS to V1.0 SP2 Update 3 or later version per vendor remediation guidance
For BIND 9 deployments outside SINEC INS, upgrade to patched versions: 9.16.46+, 9.18.22+, or 9.19.20+
Monitor DNS server CPU utilization for anomalous spikes that may indicate exploitation attempts
Implement network segmentation to limit exposure of DNS infrastructure to untrusted networks
Apply defense-in-depth practices for industrial control systems as recommended by CISA
Review and restrict DNS query sources where possible to reduce attack surface

Evidence notes

The vulnerability stems from overly high computational complexity in DNS message parsing code within `named`. Normal DNS traffic does not trigger the issue, but specially crafted queries and responses can exploit this flaw to cause excessive CPU consumption. Affected BIND 9 versions span multiple release branches: 9.0.0 through 9.16.45, 9.18.0 through 9.18.21, 9.19.0 through 9.19.19, plus corresponding S1 (subscription) versions.

Official resources

Coordinated disclosure through CISA ICS advisory ICSA-24-319-08 and Siemens SSA-915275 on November 12, 2024.