CVE-2023-36845

Juniper Junos OS on EX Series and SRX Series contains a PHP external variable modification vulnerability that allows an unauthenticated, network-based attacker to control an important environment variable. Using a crafted request, which sets the variable PHPRC, an attacker is able to modify the PHP execution environment allowing the injection und execution of code.

What this means for your business

It affects Juniper Junos OS. It matters if your company, or a supplier that handles your data, runs it.
Attackers are already using it. CISA added it to its list of flaws used in real attacks on 13 November 2023.
FIRST's prediction model gives it a 95% chance of attack attempts being seen in the next 30 days, ranking above 99% of all known flaws.

What to do

1Check whether your company or your suppliers run Juniper Junos OS.
2If you do, follow CISA's required action below. No patch reference has been published yet.
3Treat it as urgent. US federal agencies must fix it by 17 November 2023. That deadline does not apply to private companies, but it shows how seriously CISA takes it.
4Because attackers have used it, check the affected systems for signs of a break-in, not only for the update.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

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Required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

CISA’s wording, unedited.

Scoring

CVSS: Not yet scored

Dates

Published: 2023-11-13
Added to KEV: 2023-11-13
Remediation due: 2023-11-17
Sources: CISA KEV