Detect Mirasvit Full Page Cache Warmer Deserialization RCE (CVE-2026-45247) in Google Chronicle
Detects exploitation of CVE-2026-45247, a deserialization of untrusted data vulnerability in the Mirasvit Full Page Cache Warmer Magento extension. Successful exploitation allows remote attackers to execute arbitrary code by sending crafted serialized PHP objects to vulnerable endpoints. This CVE is listed in CISA KEV, indicating active exploitation in the wild.
MITRE ATT&CK
- Tactic
- Initial Access Execution Persistence
YARA-L Detection Query
rule cve_2026_45247_mirasvit_cache_warmer_deser {
meta:
author = "df00tech Detection Engineering"
description = "Detects exploitation of CVE-2026-45247 Mirasvit Full Page Cache Warmer deserialization vulnerability"
severity = "CRITICAL"
priority = "HIGH"
reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-45247"
mitre_attack = "T1190"
events:
$http.metadata.event_type = "NETWORK_HTTP"
$http.network.http.method = /POST|PUT/
(
$http.network.http.referral_url = /cache-warmer/
or $http.target.url = /cache-warmer/
or $http.target.url = /mirasvit.*warmer/
or $http.target.url = /cachewarmer/
)
(
$http.network.sent_bytes > 1000
or $http.network.http.referral_url = /O:[0-9]+:/
or $http.target.url = /rO0/
)
$http.principal.ip = $src_ip
match:
$src_ip over 10m
outcome:
$risk_score = max(80)
$event_count = count_distinct($http.metadata.id)
condition:
$http
}Chronicle YARA-L rule detecting suspicious POST/PUT requests to Mirasvit cache warmer endpoints, with signals for serialized PHP object payloads or oversized request bodies consistent with CVE-2026-45247 exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate cache warming traffic from authorized bots or internal services
- Security assessment tools scanning Magento installations
- Large legitimate API payloads to cache endpoints during catalog operations
- CDN or reverse proxy health check requests targeting warmer URLs
Other platforms for CVE-2026-45247
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Simulate Deserialization Probe to Cache Warmer Endpoint
Expected signal: POST request to /mirasvit/cachewarmer/collect visible in web access logs with payload containing 'O:8:' serialization marker; HTTP response code logged
- Test 2PHP Deserialization Gadget Chain Simulation (Lab)
Expected signal: PHP CLI process spawned with command-line containing unserialize() — visible in auditd execve records or CrowdStrike process telemetry
- Test 3Web Shell Drop Simulation Following Deserialization RCE
Expected signal: File creation event in /var/www/html/pub/ for a .php file by the web server user (www-data or nginx); auditd CREATE record or Falcon sensor file event
Unlock Pro Content
Get the full detection package for CVE-2026-45247 including response playbook, investigation guide, and atomic red team tests.