# CVE-2023-36845: Junos OS - RCE

> Live exploitation tracking for CVE-2023-36845 by the CrowdSec Live Exploit Tracker, built from real-world attack data crowdsourced from CrowdSec's global network.

Page: https://tracker.crowdsec.net/cves/CVE-2023-36845

## Key facts

- **Exploitation phase:** Limited Exploitation. The vulnerability is known but shows very limited attacker interest or exploitation activity.
- **CVSS score:** 9.8
- **Public exploit available:** Yes
- **Affected products:** Juniper Networks Junos OS
- **Weaknesses:** CWE-473 (PHP External Variable Modification)
- **Tags:** web_application

## Description

A PHP External Variable Modification vulnerability in J-Web of Juniper Networks Junos OS on EX Series allows an unauthenticated, network-based attacker to remotely execute code.

## CrowdSec analysis

[CVE-2023-36845](https://euvd.enisa.europa.eu/vulnerability/CVE-2023-36845) is a critical vulnerability impacting the J-Web interface of Juniper Networks Junos OS, allowing unauthenticated remote code execution through a crafted PHP environment variable modification.

CrowdSec has been tracking this vulnerability and its exploits since 1st of April 2025.

Insights from the CrowdSec network reveal that the attackers trying to exploit CVE-2023-36845 are composed of a fairly even mix of opportunistic and targeted actors. Some attackers employ preliminary reconnaissance, while others use indiscriminate scanning.
Data from the CrowdSec community also indicates a gradual decrease in attacks targeting CVE-2023-36845. While still present in the wild, exploitation levels have dropped noticeably week-over-week. This may signal that the vulnerability is becoming less relevant or that defenses are improving fast enough for attackers to lose interest.

Observed exploitation attempts commonly leverage URLs containing `/?phprc=/dev/fd/0`.

## Timeline

- 2023-08-17: CVE Published. CVE-2023-36845 is published to NVD.
- 2023-11-13: CISA KEV. CVE-2023-36845 is added to the Known Exploited Vulnerabilities catalog by CISA.
- 2023-11-17: CISA Remediation Deadline. Expiration of the CISA remediation deadline as described in [BOD 22-01](https://www.cisa.gov/news-events/directives/bod-22-01-reducing-significant-risk-known-exploited-vulnerabilities).
- 2025-04-01: Rule Released. CrowdSec releases a rule to detect CVE-2023-36845 exploitation attempts against the CrowdSec Network.
- 2025-04-02: CrowdSec First Seen. CrowdSec observes in-the-wild exploitation of CVE-2023-36845 for the first time.

## References

- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2023/CVE-2023-36845.yaml

## Live exploitation data

The [Live Exploit Tracker page](https://tracker.crowdsec.net/cves/CVE-2023-36845) follows observed exploitation activity for CVE-2023-36845. [Request an API key](https://tracker.crowdsec.net/request-api-key) for full access to its exploitation timeline, attacking IP addresses and blocklists.