Detection: Cisco Secure Firewall - PHP2Shell Serialized Payload Activity

Created: 2026-10-28 Last Updated: 2026-10-28 ID: 60ad33a2-6fa8-4d13-b7be-fbe5167ea0ca Author: Nasreddine Bencherchali, Splunk Type: TTP Product: Splunk Enterprise Security

Description

This analytic detects suspicious PHP web application requests using Cisco Secure Firewall Threat Defense Intrusion Events. The matching network signature identifies a serialized input pattern associated with attempts to exploit PHP request handling. Investigate the source, targeted application, and related web server activity to determine whether the request was part of PHP2Shell exploitation.

Search

 1`cisco_secure_firewall` EventType=IntrusionEvent SignatureID=67359
 2
 3| fillnull
 4
 5| stats min(_time) as firstTime
 6        max(_time) as lastTime
 7        values(SignatureID) as SignatureID
 8        values(signature) as signature
 9        values(class_desc) as class_desc
10        values(MitreAttackGroups) as MitreAttackGroups
11        values(InlineResult) as InlineResult
12        values(InlineResultReason) as InlineResultReason
13        values(src) as src
14        values(dest_port) as dest_port
15        values(rule) as rule
16        values(transport) as transport
17        values(app) as app
18        by dest
19
20| `security_content_ctime(firstTime)`
21
22| `security_content_ctime(lastTime)`
23
24| `cisco_secure_firewall___php2shell_serialized_payload_activity_filter`

Data Source

Name	Platform	Sourcetype	Source
Cisco Secure Firewall Threat Defense Intrusion Event	Network	`'cisco:sfw:estreamer'`	`'not_applicable'`

Macros Used

Name	Value
cisco_secure_firewall	`sourcetype="cisco:sfw:estreamer"`
cisco_secure_firewall___php2shell_serialized_payload_activity_filter	`search *`

cisco_secure_firewall___php2shell_serialized_payload_activity_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1190	Exploit Public-Facing Application	Initial Access

Delivery

DE.CM

CIS 13

CVE

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Finding (Notable)	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Intermediate Finding (Risk Event)	No

TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

This search requires Cisco Secure Firewall Threat Defense logs with IntrusionEvent data. It uses the cisco_secure_firewall input macro, configure it for your environment (index, source, sourcetype). Ensure intrusion events are collected via the Splunk Add-on for Cisco Security Cloud (https://splunkbase.splunk.com/app/7404) and that the relevant intrusion policy is enabled.

Known False Positives

Security testing or applications that legitimately submit serialized PHP data may trigger this signature. Review the request context and the targeted service.

Associated Analytic Story

Finding

Title	Entity Field	Entity Type	Risk Score
Suspicious PHP serialized input from [$src$] targeting [$dest$]	dest	system	50

Threat Objects

Field	Type
src	ip_address
signature	signature

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`not_applicable`	`cisco:sfw:estreamer`
Integration	✅ Passing	Dataset	`not_applicable`	`cisco:sfw:estreamer`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub |

Version: 1