CVE-2023-36851
Published: November 13, 2023
Official Description
Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that 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 arbitrary files via J-Web, leading to a loss of integrity for a certain part of the file system, which may allow chaining to other vulnerabilities.
CISA KEV Advisory
Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability
Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that 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 arbitrary files via J-Web, leading to a loss of integrity for a certain part of the file system, which may allow chaining to other vulnerabilities.
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Risk Analysis
This vulnerability in Juniper Junos OS on SRX Series devices allows an unauthenticated, network-based attacker to upload arbitrary files via J-Web due to missing authentication for a critical function. This can lead to a loss of file system integrity and potentially enable further attacks. The high severity and confirmed exploitation in the wild necessitate immediate action, with an EPSS score of 0.14935 indicating a notable exploitation likelihood.
This vulnerability is actively exploited in the wild and is present in CISA's KEV catalog. It is remotely exploitable without authentication.
Apply the latest security updates for Juniper Junos OS on SRX Series devices. Restrict access to the J-Web interface and ensure proper authentication mechanisms are in place for critical functions.
Technical Analysis
CVE-2023-36851 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2023-36851 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (2)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2023-36851 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1