Vulnerability in ntp (DEBIAN-CVE-2016-2517)

Summary

Vulnerability in ntp (DEBIAN-CVE-2016-2517). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1:4.2.8p7+dfsg-1 or later.

Original description

The description as published by the source.

NTP before 4.2.8p7 and 4.3.x before 4.3.92 allows remote attackers to cause a denial of service (prevent subsequent authentication) by leveraging knowledge of the controlkey or requestkey and sending a crafted packet to ntpd, which changes the value of trustedkey, controlkey, or requestkey. NOTE: this vulnerability exists because of a CVE-2016-2516 regression.

Source: OSV.dev (Open Source Vulnerabilities) OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as DEBIAN-CVE-2016-2517 has been found in ntp.
Risk of unauthorized operations or information disclosure.
What to do: upgrade ntp to 1:4.2.8p7+dfsg-1 or later.
If unsure, ask your IT team or search "ntp DEBIAN-CVE-2016-2517" on the vendor's site.

DEBIAN-CVE-2016-2517 (ntp)
Attack vector: remote (network-reachable) / no user interaction
Patched: 1:4.2.8p7+dfsg-1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in ntp.

📍 Affected scope

Check the vendor advisory for the affected versions of ntp.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1:4.2.8p7+dfsg-1.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'ntp' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'ntp' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で ntp を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade ntp to 1:4.2.8p7+dfsg-1
```
ステージング環境で 1:4.2.8p7+dfsg-1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Debian:11 ntp

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:4.2.8p7+dfsg-1"}]}]

References

advisory security-tracker.debian.org