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JunosOperating system · Juniper

CVE-2018-0051

MEDIUM · 5.9 CVSS v3.0 Published 2018-10-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
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
A Denial of Service vulnerability in the SIP application layer gateway (ALG) component of Junos OS based platforms allows an attacker to crash MS-PIC, MS-MIC, MS-MPC, MS-DPC or SRX flow daemon (flowd) process. This issue affects Junos OS devices with NAT or stateful firewall configuration in combination with the SIP ALG enabled. SIP ALG is enabled by default on SRX Series devices except for SRX-HE devices. SRX-HE devices have SIP ALG disabled by default. The status of ALGs in SRX device can be obtained by executing the command: show security alg status Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D77; 12.3X48 versions prior to 12.3X48-D70; 15.1X49 versions prior to 15.1X49-D140; 15.1 versions prior to 15.1R4-S9, 15.1R7-S1; 15.1F6; 16.1 versions prior to 16.1R4-S9, 16.1R6-S1, 16.1R7; 16.2 versions prior to 16.2R2-S7, 16.2R3; 17.1 versions prior to 17.1R2-S7, 17.1R3; 17.2 versions prior to 17.2R1-S6, 17.2R2-S4, 17.2R3; 17.3 versions prior to 17.3R1-S5, 17.3R2-S2, 17.3R3; 17.4 versions prior to 17.4R2. No other Juniper Networks products or platforms are affected by this issue.

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

A Denial of Service vulnerability in the SIP Application Layer Gateway (ALG) component of Junos OS allows an attacker to crash the flow daemon (flowd) process on affected SRX Series devices. The vulnerability is triggered when the SIP ALG is enabled (default on SRX Series except SRX-HE) in combination with NAT or stateful firewall configuration, causing the MS-PIC, MS-MIC, MS-MPC, MS-DPC, or SRX flowd process to crash.

MitigationUpgrade Junos OS to the specified fixed versions (12.1X46-D77, 12.3X48-D70, 15.1X49-D140, etc.) or disable the SIP ALG if not required using 'set security alg sip disable' command.

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
JunosOperating system
Affected:= 12.1x46= 12.3x48= 15.1x49= 15.1= 16.1= 16.2= 17.1= 17.2= 17.3= 17.4

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

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

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

  1. Verify Junos OS version
    Run 'show version' or 'show version detail' to identify the installed Junos OS version
    Affected if The version matches or falls within the affected ranges: 12.1x46, 12.3x48, 15.1x49, 15.1, 16.1, 16.2, 17.1, 17.2, 17.3, or 17.4
  2. Confirm device is SRX Series
    Run 'show chassis hardware' or 'show system information' to identify the device model
    Affected if The device is an SRX Series device (the vulnerability does not affect SRX-HE)
  3. Check if SIP ALG is enabled
    Run 'show security alg sip' or inspect the configuration under 'security alg sip' hierarchy
    Affected if SIP ALG is enabled (not disabled with 'set security alg sip disable') - this is the default on SRX Series except SRX-HE
  4. Verify NAT or stateful firewall is configured
    Run 'show security nat' and 'show security policies' to check for NAT rules or stateful firewall policies
    Affected if NAT or stateful firewall policies are configured - this is required together with enabled SIP ALG for the vulnerability to be triggered

The environment is affected if the device runs an affected Junos OS version, is an SRX Series (non-SRX-HE), has SIP ALG enabled, and has NAT or stateful firewall configuration present.

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

Upgrade Junos OS to the specified fixed versions (12.1X46-D77, 12.3X48-D70, 15.1X49-D140, etc.) or disable the SIP ALG if not required using 'set security alg sip disable' command.

Fix this in Junos Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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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-2018-0051 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