CVE-2023-36851Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability
CVE-2023-36851 is a missing authentication in Juniper Junos OS, rated medium (5.3 on CVSS 3.1).
Why this priority: Exploited in the wild: listed in CISA's KEV catalog.
Published · Updated · NVD status: Analyzed
What it is
A function that should require sign-in can be called by anyone.
How it is reached
An attacker can exploit it over the network, without an account, and nobody has to click anything.
What an attacker gains
The direct impact is limited: partial access to data or a partial outage. In practice, this kind of flaw lets an attacker act as a signed-in user, or an administrator, without valid credentials.
Is it being exploited?
CISA added it to the Known Exploited Vulnerabilities catalog on 2023-11-13: it is being exploited in the wild. It can be exploited automatically, at scale. EPSS estimates a 1.1% chance of exploitation activity in the next 30 days, higher than 67% of scored CVEs.
What to do
- Treat it as urgent: it is on CISA's KEV list. CISA's deadline for US federal agencies: 2023-11-17.
- Upgrade Juniper Junos OS to a fixed version for your release line (21.2R3-S8, 21.4R3-S6, 22.1R3-S5).
- Until it is patched, keep it off the internet or behind a VPN, allowlist or authenticating proxy.
- Check exposed instances for signs of compromise, not only for the version.
Description from NVD
A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity.
With a specific request to
webauth_operation.php
that doesn't require authentication, an attacker is able to upload and download arbitrary files via J-Web, leading to a loss of
integrity or confidentiality, which may allow chaining to other vulnerabilities.
This issue affects Juniper Networks Junos OS on SRX Series:
*
21.2 versions prior to 21.2R3-S8; * 21.4
versions prior to
21.4R3-S6; * 22.1
versions prior to
22.1R3-S5; * 22.2
versions prior to
22.2R3-S3; * 22.3
versions prior to
22.3R3-S2; * 22.4 versions prior to 22,4R2-S2, 22.4R3; * 23.2 versions prior to
23.2R1-S2, 23.2R2.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Network edge devices: VPNs, firewalls, routers and gateways. They sit between the internet and internal networks, so a flaw in one is often the first step into everything behind it.
- Operating systems on servers, workstations or devices. Everything on the host inherits the flaw.
- Sign-in, session and token handling. The flaw sits between anonymous callers and authenticated sessions.
- Identity providers and SSO. The flaw sits between anonymous callers and authenticated sessions.
Trust boundaries in play
- Internet-facing entry points. No account is needed. Any instance reachable from outside your perimeter, through a load balancer, gateway, VPN or exposed admin port, is in scope.
- Between anonymous callers and authenticated sessions. An attacker who crosses it can act as a signed-in user, or an administrator, without valid credentials.
Questions to answer about your own systems
- Where does Juniper Junos OS run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.