Security readout for executives and security teams
Plain-English summary
This flaw lets a low-privileged local CLI user on affected Juniper devices overwrite local files with root-level effect. The business risk is device instability or a sustained denial of service requiring manual recovery. Exposure depends on affected Junos versions and whether jdhcpd is running.
Executive priority
Treat this as a high-priority infrastructure maintenance issue where affected Juniper devices support critical network paths. It is not presented as remotely exploitable, but a low-privileged local user could cause serious operational disruption.
Technical view
CVE-2021-31360 is improper privilege management in the Junos OS and Junos OS Evolved CLI local file processing path. With local low-privileged access, an attacker may overwrite files as root, affecting integrity and availability. Juniper states systems are vulnerable only when jdhcpd is running.
Likely exposure
Most exposed environments are Juniper routing or switching estates running listed vulnerable Junos OS or Junos OS Evolved releases with local CLI users and jdhcpd active. Internet exposure alone is not the key factor because the CVSS vector is local access with low privileges.
Exploitation context
The supplied sources do not show active exploitation, public exploit use, or CISA KEV listing. Exploitation requires local low-privileged access, but successful abuse can affect root-owned files and may cause sustained device denial of service.
Researcher notes
Key validation pivots are product branch, fixed-release threshold, local CLI privilege model, and jdhcpd process state. Evidence is strongest for affected versions and prerequisites; supplied sources do not provide exploit details or independent exploitation telemetry.
Mitigation direction
- Upgrade affected devices to the Juniper fixed release for their supported branch.
- Prioritize devices where jdhcpd is running and low-privileged CLI access exists.
- Restrict unnecessary local CLI accounts and review least-privilege access.
- Check Juniper advisory JSA11222 for branch-specific remediation guidance.
- Plan manual recovery procedures for devices at risk of sustained DoS.
Validation and detection
- Inventory Junos OS and Junos OS Evolved versions across managed devices.
- Compare each version against the vulnerable ranges in Juniper JSA11222.
- Confirm whether jdhcpd is running on each potentially affected device.
- Review local CLI users and roles on affected devices.
- After upgrade, verify the device runs a fixed release for its branch.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-20: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-269: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-31360 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H1.85.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.1HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.juniper.net/JSA11222CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Improper Privilege Management
Improper Privilege Management represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.