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JunosOperating system · Juniper

CVE-2021-0204

HIGH · 7.8 CVSS v3.1 Published 2021-01-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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 sensitive information disclosure vulnerability in delta-export configuration utility (dexp) of Juniper Networks Junos OS may allow a locally authenticated shell user the ability to create and read database files generated by the dexp utility, including password hashes of local users. Since dexp is shipped with setuid permissions enabled and is owned by the root user, this vulnerability may allow a local privileged user the ability to run dexp with root privileges and access sensitive information in the dexp database. This issue affects Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S8; 15.1X49 versions prior to 15.1X49-D230; 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S12, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S6; 18.2X75 versions prior to 18.2X75-D34; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R2-S7, 18.4R3-S6; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S3; 19.2 versions prior to 19.2R1-S5, 19.2R3-S1; 19.3 versions prior to 19.3R2-S5, 19.3R3-S1; 19.4 versions prior to 19.4R1-S3, 19.4R2-S2, 19.4R3-S1; 20.1 versions prior to 20.1R1-S4, 20.1R2; 20.2 versions prior to 20.2R1-S2, 20.2R2.

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 locally authenticated attacker with shell access can exploit the dexp utility in Juniper Junos OS to create and read database files containing sensitive information, including password hashes of local users. Since dexp has setuid permissions and is owned by root, a local privileged user can run it with root privileges to access these sensitive files.

MitigationUpgrade Junos OS to a patched version as specified in the vendor advisory; apply the appropriate version for each affected branch.

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:= 15.1= 17.3= 17.4= 18.1= 18.2= 18.3= 18.4= 19.1= 19.2= 19.3= 19.4= 20.1

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/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 checks

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

  1. Verify Junos OS version
    Run 'show version' on the device CLI and note the software version
    Affected if The installed version matches one of these: 15.1, 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, 19.3, 19.4, or 20.1
  2. Locate the dexp binary
    Run 'which dexp' or 'find /usr -name dexp 2>/dev/null' to find the dexp utility path
    Affected if The dexp binary exists on the system (this is required for the vulnerability to be exploitable)
  3. Check dexp permissions for setuid bit
    Run 'ls -la <path-to-dexp>' and look for 's' in the owner permissions (for example: -rwsr-xr-x). The dexp binary must have setuid permissions and be owned by root for the flaw to apply.
    Affected if The dexp binary has setuid permissions (-rws... or similar) and is owned by root
  4. Audit system for unexpected database files
    Search for .db or database files in /var, /tmp, or home directories that were not created by an administrator. Run 'find /var -name "*.db" -mtime -30' to find recently created database files.
    Affected if Unexpected database files exist that may contain password hashes or other sensitive data
  5. Review user password hashes for changes
    Check /etc/passwd or the vendor-specific user database for local accounts. Compare current password hash fields against known-good backups or documentation.
    Affected if Password hash fields have been modified unexpectedly or contain unfamiliar values

A device is affected if it runs any of the listed Junos versions AND has the dexp binary present with root-owned setuid permissions.

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 a patched version as specified in the vendor advisory; apply the appropriate version for each affected branch.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,180
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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-2021-0204 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