Sigma rule: Suspicious Process By Web Server Process

Rule

Title

Suspicious Process By Web Server Process

Status

test

Level

high

Author

Thomas Patzke, Florian Roth (Nextron Systems), Zach Stanford @svch0st, Tim Shelton, Nasreddine Bencherchali (Nextron Systems)

Date

2019-01-16

Modified

2024-11-26

File

rules/windows/process_creation/proc_creation_win_webshell_susp_process_spawned_from_webserver.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects potentially suspicious processes being spawned by a web server process which could be the result of a successfully placed web shell or exploitation

Log source

product

windows

category

process_creation

Detection

selection_webserver_image:
    ParentImage|endswith:
        - '\caddy.exe'
        - '\httpd.exe'
        - '\nginx.exe'
        - '\php-cgi.exe'
        - '\php.exe'
        - '\tomcat.exe'
        - '\UMWorkerProcess.exe'  # https://www.fireeye.com/blog/threat-research/2021/03/detection-response-to-exploitation-of-microsoft-exchange-zero-day-vulnerabilities.html
        - '\w3wp.exe'
        - '\ws_TomcatService.exe'
selection_webserver_characteristics_tomcat1:
    ParentImage|endswith:
        - '\java.exe'
        - '\javaw.exe'
    ParentImage|contains:
        - '-tomcat-'
        - '\tomcat'
selection_webserver_characteristics_tomcat2:
    ParentImage|endswith:
        - '\java.exe'
        - '\javaw.exe'
    ParentCommandLine|contains:
        - 'CATALINA_HOME'
        - 'catalina.home'
        - 'catalina.jar'
selection_anomaly_children:
    Image|endswith:
        - '\arp.exe'
        - '\at.exe'
        - '\bash.exe'
        - '\bitsadmin.exe'
        - '\certutil.exe'
        - '\cmd.exe'
        - '\cscript.exe'
        - '\dsget.exe'
        - '\hostname.exe'
        - '\nbtstat.exe'
        - '\net.exe'
        - '\net1.exe'
        - '\netdom.exe'
        - '\netsh.exe'
        - '\nltest.exe'
        - '\ntdsutil.exe'
        - '\powershell_ise.exe'
        - '\powershell.exe'
        - '\pwsh.exe'
        - '\qprocess.exe'
        - '\query.exe'
        - '\qwinsta.exe'
        - '\reg.exe'
        - '\rundll32.exe'
        - '\sc.exe'
        - '\sh.exe'
        - '\wmic.exe'
        - '\wscript.exe'
        - '\wusa.exe'
filter_main_fp_1:
    ParentImage|endswith: '\java.exe'
    CommandLine|endswith: 'Windows\system32\cmd.exe /c C:\ManageEngine\ADManager "Plus\ES\bin\elasticsearch.bat -Enode.name=RMP-NODE1 -pelasticsearch-pid.txt'
filter_main_fp_2:
    ParentImage|endswith: '\java.exe'
    CommandLine|contains|all:
        - 'sc query'
        - 'ADManager Plus'
condition: 1 of selection_webserver_* and selection_anomaly_children and not 1 of filter_main_*

False positives (as the rule lists them)

• Particular web applications may spawn a shell process legitimately

Tags

• attack.persistence
• attack.initial-access
• attack.t1505.003
• attack.t1190

MITRE ATT&CK ids this rule names

• T1190
• T1505.003

References

• https://media.defense.gov/2020/Jun/09/2002313081/-1/-1/0/CSI-DETECT-AND-PREVENT-WEB-SHELL-MALWARE-20200422.PDF

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_webshell_susp_process_spawned_from_webserver.yml