CVE-2020-25758
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn issue was discovered on D-Link DSR-250 3.17 devices. Insufficient validation of configuration file checksums could allow a remote, authenticated attacker to inject arbitrary crontab entries into saved configurations before uploading. These entries are executed as root.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceD-Link DSR-250 3.17 devices fail to properly validate configuration file checksums. An authenticated remote attacker can modify saved configuration files to inject malicious crontab entries, which are executed with root privileges when the tampered configuration is uploaded to the device.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 3.17<= 3.17<= 3.17<= 3.17<= 3.17all versions<= 3.17<= 3.17CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify device model and firmware versionAccess the D-Link DSR web interface and navigate to Status > System Information, or run 'show system' via CLI to retrieve the exact model number and firmware version.Affected if The device is a DSR-150, DSR-150n, DSR-250, DSR-250n, DSR-500, DSR-500ac, or DSR-1000 with firmware version 3.17 or lower, or any DSR-500n version.
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Confirm web management interface exposureCheck if the D-Link DSR web administration interface (HTTPS on port 443) is accessible from untrusted or external networks by reviewing firewall rules and port forwarding configurations.Affected if The administrative interface is accessible from networks outside the trusted administrative zone.
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Inspect crontab entries for malicious activityAccess the device via CLI or SSH and run 'show running-config | include cron' or view the crontab file directly to inspect scheduled tasks.Affected if Any crontab entries exist that were not explicitly configured by legitimate administrators, or entries pointing to unknown scripts or external URLs.
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Review configuration file integrityDownload the current configuration file from the device (Maintenance > Backup/Restore) and compare its checksum (MD5 or SHA256) against previously known-good backups, or manually inspect the file for unexpected crontab sections.Affected if The configuration file checksum differs from known-good backups without authorized changes, or the config contains unexpected cron or scheduled task definitions.
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Check for unauthorized configuration uploadsReview device logs (Status > Logs or syslog if configured) for events indicating configuration file uploads or restores, and cross-reference with authorized administrator activity.Affected if Configuration upload events appear in logs that do not correspond to known administrative actions.
You are affected if you are running a DSR-150, DSR-150n, DSR-250, DSR-250n, DSR-500, DSR-500ac, or DSR-1000 on firmware 3.17 or lower (or any DSR-500n version) and the device web interface is accessible to authenticated users who could upload tampered configuration files containing malicious crontab entries.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor firmware updates when available. Until then, strictly limit administrative access to trusted personnel only and monitor for unauthorized configuration changes.
- Consultation2.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,480.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-25758 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-25758 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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