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CVE-2016-3081 exploitation attempt

SIGhighconfidence 90/100generated 2026-10-18

Web request carrying the exploit observable of CVE-2016-3081 (CISA KEV, EPSS 0.95, public PoC), taken from the public nuclei template.

ATT&CK: T1190 mitre ↗
Linked CVE: CVE-2016-3081
False positives: Keys on the distinctive part of the exploit request only (path traversal, exploit syntax in the query, an unusual parameter) — never on an endpoint the product serves in normal use. Needs raw request-URI logging (some web servers normalise ../ away). Scanners hitting the internet produce true-positive ATTEMPTS: correlate with sc-status / response size before declaring compromise.

Sigma rule

skopnix-sigma-cve-cve-2016-3081-b9df2e80.ymldownload .yml ↓

title: Skopnix - CVE-2016-3081 exploitation attempt
id: 21b6bbec-a769-5a27-92b8-1fc24e1585c3
status: experimental
description: Web request carrying the exploit observable of CVE-2016-3081 (CISA KEV, EPSS 0.95, public PoC), taken from the public nuclei template.
references:
  - https://skopnix.com/cve/CVE-2016-3081
  - https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2016/CVE-2016-3081.yaml
  - https://nvd.nist.gov/vuln/detail/CVE-2016-3081
author: skopnix
date: '2026-10-18'
tags:
  - attack.initial-access
  - attack.t1190
  - cve.2016-3081
logsource:
  category: webserver
detection:
  selection_1:
    cs-uri-stem|contains: /index.action
    cs-uri-query|contains: method:%23_memberAccess%3d@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS,%23res%3d%40org.apache.struts2.ServletActionContext%40getResponse(),%23res.setCharacterEncoding(%23parameters.encoding%5B0%5D),%23w%3d%23res.getWriter(),%23s%3dnew+java.util.Scanner(@java.lang.Runtime@getRuntime().exec(%23parameters.cmd%5B0%5D).getInputStream()).useDelimiter(%23parameters.pp%5B0%5D),%23str%3d%23s.hasNext()%3f%23s.next()%3a%23parameters.ppp%5B0%5D,%23w.print(%23str),%23w.close(),1?%23xx:%23request.toString
  condition: selection_1
falsepositives:
  - Vulnerability scanners and authorised penetration tests (attempts, not compromise)
level: critical

How to deploy on Sigma

1.Convert for your SIEM with sigma-cli / pySigma, e.g. sigma convert -t splunk -p sysmon rule.yml.
2.Run it as a hunt first: every rule ships as status experimental.
3.Promote to an alert once a week of results is clean on your data.

Check · The processing pipeline must map the logsource (firewall, dns, proxy, webserver, process_creation) to your field names.

Sigma rule

How to deploy on Sigma

References