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Debian LinuxOperating system · Debian

CVE-2018-10242

HIGH · 7.5 CVSS v3.0 Published 2019-04-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
Suricata version 4.0.4 incorrectly handles the parsing of the SSH banner. A malformed SSH banner can cause the parsing code to read beyond the allocated data because SSHParseBanner in app-layer-ssh.c lacks a length check.

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 confidence

Suricata 4.0.4 contains a buffer over-read vulnerability in the SSHParseBanner() function in app-layer-ssh.c. The function fails to validate buffer length before parsing SSH banners, allowing a malformed SSH banner to cause reads beyond allocated memory boundaries.

MitigationUpdate Suricata to a version containing the fix for this vulnerability, or implement input validation to reject SSH banners that exceed expected length bounds before reaching the parsing function.

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
Debian LinuxOperating system
Affected:= 8.0
SuricataApplication
Affected:= 4.0.4

CVSS 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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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 checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Suricata version
    Run 'suricata --version' or check the package manager (dpkg -l suricata, rpm -qi suricata)
    Affected if Version is exactly 4.0.4 (or an unpatched version within the 4.0.x series before fix)
  2. Verify SSH protocol parser is enabled
    Inspect suricata.yaml configuration file for 'app-layer.protocols.ssh.enabled: true' or check if SSH parser is loaded in the config
    Affected if SSH protocol parsing is enabled in the Suricata configuration
  3. Confirm SSH traffic or rules are in use
    Check if there are SSH-related rules loaded (grep -r 'ssh' in rules directory) or if Suricata is logging SSH transaction data
    Affected if Suricata has SSH rules loaded or is actively parsing SSH traffic
  4. Check for SSH banner logging
    Look for eve.json or ssh.log outputs that contain SSH banner data from parsed sessions
    Affected if Suricata is logging SSH banner information from parsed sessions

You are affected if Suricata version 4.0.4 is installed AND SSH protocol parsing is enabled and actively processing SSH traffic, allowing malformed SSH banners to trigger the buffer over-read.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Suricata to a version containing the fix for this vulnerability, or implement input validation to reject SSH banners that exceed expected length bounds before reaching the parsing function.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-10242 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data