NVD / CVE Program· CNA juniper

CVE-2020-1631: Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) services

Noroxi assessment

Priority: This week (action score 70/100)

CISA has confirmed exploitation in the wild (Mar 25, 2022). Remediation deadline for US federal agencies: Apr 15, 2022.
Probability of exploitation in the next 30 days: 4.8% (FIRST EPSS); higher than 92% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

A vulnerability in the HTTP/HTTPS service used by J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Zero Touch Provisioning (ZTP) allows an unauthenticated attacker to perform local file inclusion (LFI) or path traversal. Using this vulnerability, an attacker may be able to inject commands into the httpd.log, read files with 'world' readable permission file or obtain J-Web session tokens. In the case of command injection, as the HTTP service runs as user 'nobody', the impact of this command injection is limited. (CVSS score 5.3, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) In the case of reading files with 'world' readable permission, in Junos OS 19.3R1 and above, the unauthenticated attacker would be able to read the configuration file. (CVSS score 5.9, vector CVSS:3.1/ AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N) If J-Web is enabled, the attacker could gain the same level of access of anyone actively logged into J-Web. If an administrator is logged in, the attacker could gain administrator access to J-Web. (CVSS score 8.8, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) This issue only affects Juniper Networks Junos OS devices with HTTP/HTTPS services enabled. Junos OS devices with HTTP/HTTPS services disabled are not affected. If HTTP/HTTPS services are enabled, the following command will show the httpd processes: user@device> show system processes | match http 5260 - S 0:00.13 /usr/sbin/httpd-gk -N 5797 - I 0:00.10 /usr/sbin/httpd --config /jail/var/etc/httpd.conf To summarize: If HTTP/HTTPS services are disabled, there is no impact from this vulnerability. If HTTP/HTTPS services are enabled and J-Web is not in use, this vulnerability has a CVSS score of 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N). If J-Web is enabled, this vulnerability has a CVSS score of 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). Juniper SIRT has received a single report of this vulnerability being exploited in the wild. Out of an abundance of caution, we are notifying customers so they can take appropriate actions. Indicators of Compromise: The /var/log/httpd.log may have indicators that commands have injected or files being accessed. The device administrator can look for these indicators by searching for the string patterns "=*;*&" or "*%3b*&" in /var/log/httpd.log, using the following command: user@device> show log httpd.log | match "=*;*&|=*%3b*&" If this command returns any output, it might be an indication of malicious attempts or simply scanning activities. Rotated logs should also be reviewed, using the following command: user@device> show log httpd.log.0.gz | match "=*;*&|=*%3b*&" user@device> show log httpd.log.1.gz | match "=*;*&|=*%3b*&" Note that a skilled attacker would likely remove these entries from the local log file, thus effectively eliminating any reliable signature that the device had been attacked. This issue affects Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S16; 12.3X48 versions prior to 12.3X48-D101, 12.3X48-D105; 14.1X53 versions prior to 14.1X53-D54; 15.1 versions prior to 15.1R7-S7; 15.1X49 versions prior to 15.1X49-D211, 15.1X49-D220; 16.1 versions prior to 16.1R7-S8; 17.2 versions prior to 17.2R3-S4; 17.3 versions prior to 17.3R3-S8; 17.4 versions prior to 17.4R2-S11, 17.4R3-S2; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S4; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R1-S7, 18.4R3-S2 ; 18.4 version 18.4R2 and later versions; 19.1 versions prior to 19.1R1-S5, 19.1R3-S1; 19.1 version 19.1R2 and later versions; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2; 20.1 versions prior to 20.1R1-S1, 20.1R2.

CriticalCVSS 9.8 · v3.1KEVWeaponized No fix recorded

BDU:2023-00722

Published: May 4, 2020
Updated: Jun 16, 2026
EPSS: 4.8% · 92th percentile
CWE: CWE-22

Report tools

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Action score

This week

Don’t wait for the next maintenance window.

CVSS: 39 / 40 · 9.8 / 10
CISA KEV: 30 / 30 · Listed
EPSS: 1 / 30 · 4.8%

CISA SSVC decision

Exploitation: active
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 9.8
CNA · juniper: 8.8; 1.0 point gap

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Mar 25, 2022. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Apr 15, 2022.

Get told when this record changes

In CISA KEV: exploitation in the wild confirmed
Weaponized exploit exists
No fixed version yet

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
juniper	junos	cpe:2.3:o:juniper:junos

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

juniper junos12.3
juniper junos12.3x48
juniper junos14.1x53
juniper junos15.1
juniper junos15.1x49
juniper junos16.1
juniper junos17.2
juniper junos17.3
juniper junos17.4
juniper junos18.1
juniper junos18.2
juniper junos18.3
juniper junos18.4
juniper junos19.1
juniper junos19.2
juniper junos19.3
juniper junos19.4
juniper junos20.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (juniper). Independent of NVD's CPE analysis and usually ahead of it.

Juniper Networks Junos OS
- 12.3 and later · before 12.3R12-S16affected
- 12.3X48 and later · before 12.3X48-D101, 12.3X48-D105affected
- 14.1X53 and later · before 14.1X53-D54affected
- 15.1 and later · before 15.1R7-S7affected
- 15.1X49 and later · before 15.1X49-D211, 15.1X49-D220affected
- 16.1 and later · before 16.1R7-S8affected
- 17.2 and later · before 17.2R3-S4affected
- 17.3 and later · before 17.3R3-S8affected
- 17.4 and later · before 17.4R2-S11, 17.4R3-S2affected
- 18.1 and later · before 18.1R3-S10affected

Same product

juniper: all records

Other highest-scoring records for the same primary product.

CVE-2023-36845Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to control an important environment variableKEV
98Now
CVE-2023-36846Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesKEV
79This week
CVE-2023-36844Junos OS: EX Series: A PHP vulnerability in J-Web allows an unauthenticated attacker to control important environment variablesKEV
78This week

Published before and after this one in the same product

← EarlierCVE-2020-1633Apr 9, 2020 · Junos OS: MX Series: Crafted packets traversing a Broadband Network Gateway (BNG) configured with IPv6 NDP proxy could lead to Denial of Service
26Monitor
← EarlierCVE-2020-1632Apr 15, 2020 · Junos OS and Junos OS Evolved: Invalid BGP UPDATE sent to peer device may cause BGP session to terminate.
34Monitor
Later →CVE-2020-1640Jul 17, 2020 · Junos OS: Receipt of certain genuine BGP packets from any BGP Speaker causes RPD to crash.
30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedMay 4, 2020
CISA KEVMar 25, 2022+690 d
TodayNov 6, 2026+2377 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Laing Bian and Leishen Song (@rayh4c)360 ATA for reporting this issue.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const file = path.join(ROOT, req.query.name);
2res.sendFile(file);

Fixed

1const file = path.resolve(ROOT, req.query.name);
2if (!file.startsWith(ROOT + path.sep)) {
3  return res.sendStatus(400);
4}
5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

kb.juniper.net/JSA11021

Show all references (1 more)

www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-1631

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records