CVE-2015-5477: ISC BIND Data‑Processing Errors Enable Remote DoS via TKEY Queries
What It Is – ISC BIND (the widely deployed DNS server) contains a data‑processing flaw that can be triggered by specially‑crafted TKEY queries. The flaw allows a remote, unauthenticated attacker to crash the name service, resulting in a denial‑of‑service condition.
Exploitability – The vulnerability is exploitable over the network without credentials. No public exploit code has been released, but the attack vector is trivial to construct. CVSS v3.1 base score is 5.3 (Moderate).
Affected Products – ISC BIND versions prior to the patch released in 2015 (all supported releases at the time).
Why It Matters for Trust & Control Assurance
- Continuous monitoring of DNS health and patch status provides auditable evidence that the service‑availability control is being exercised.
- Demonstrating timely remediation of known flaws satisfies the “incident response and service continuity” control objective that underpins many frameworks (e.g., NIST CSF 2.0).
- A defensible audit trail of vulnerability management helps enterprise buyers verify that the organization can maintain the availability of critical infrastructure.
Recommended Actions
- Apply the ISC‑provided patch or upgrade to the latest BIND release that includes the fix.
- Verify that DNS logging is enabled and that alerts fire on abnormal TKEY query volumes.
- Incorporate the patch‑deployment step into your change‑management workflow and retain evidence of completion for audit purposes.
- Conduct a post‑remediation DoS test to confirm the service remains resilient.
Source: CISA KEV – CVE‑2015‑5477