| ID | Technique | Tactic |
|---|---|---|
| T1505.003 | Web Shell | Persistence |
| T1505 | Server Software Component | Persistence |
| T1190 | Exploit Public-Facing Application | Initial Access |
| T1133 | External Remote Services | Initial Access |
Detection: Web JSP Request via URL
Description
The following analytic identifies URL requests associated with CVE-2022-22965 (Spring4Shell) exploitation attempts, specifically targeting webshell access on a remote webserver. It detects HTTP GET requests with URLs containing ".jsp?cmd=" or "j&cmd=" patterns. This activity is significant as it indicates potential webshell deployment, which can lead to unauthorized remote command execution. If confirmed malicious, attackers could gain control over the webserver, execute arbitrary commands, and potentially escalate privileges, leading to severe data breaches and system compromise.
Search
1
2| tstats count from datamodel=Web where Web.http_method IN ("GET") Web.url IN ("*.jsp?cmd=*","*j&cmd=*") by Web.http_user_agent Web.http_method, Web.url,Web.url_length Web.src, Web.dest sourcetype
3| `drop_dm_object_name("Web")`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| `web_jsp_request_via_url_filter`
Data Source
| Name | Platform | Sourcetype | Source |
|---|---|---|---|
| Nginx Access | N/A | 'nginx:plus:kv' |
'/var/log/nginx/access.log' |
Macros Used
| Name | Value |
|---|---|
| security_content_ctime | convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
| web_jsp_request_via_url_filter | search * |
web_jsp_request_via_url_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
KillChainPhase.DELIVERY
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_13
APT28
APT29
APT32
APT38
APT39
APT5
Agrius
BackdoorDiplomacy
CURIUM
Deep Panda
Dragonfly
Ember Bear
FIN13
Fox Kitten
GALLIUM
HAFNIUM
Kimsuky
Leviathan
Magic Hound
Moses Staff
OilRig
Sandworm Team
Threat Group-3390
Tonto Team
Tropic Trooper
Volatile Cedar
Volt Typhoon
APT28
APT29
APT39
APT41
APT5
Agrius
Axiom
BackdoorDiplomacy
BlackTech
Blue Mockingbird
Cinnamon Tempest
Dragonfly
Earth Lusca
Ember Bear
FIN13
FIN7
Fox Kitten
GALLIUM
GOLD SOUTHFIELD
HAFNIUM
INC Ransom
Ke3chang
Kimsuky
Magic Hound
Moses Staff
MuddyWater
Play
Rocke
Sandworm Team
Threat Group-3390
ToddyCat
Volatile Cedar
Volt Typhoon
Winter Vivern
menuPass
APT18
APT28
APT29
APT41
Akira
Chimera
Dragonfly
Ember Bear
FIN13
FIN5
GALLIUM
GOLD SOUTHFIELD
Ke3chang
Kimsuky
LAPSUS$
Leviathan
OilRig
Play
Sandworm Team
Scattered Spider
TeamTNT
Threat Group-3390
Volt Typhoon
Wizard Spider
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 Notable | Yes |
| Rule Title | %name% |
| Rule Description | %description% |
| Notable Event Fields | user, dest |
| Creates Risk Event | True |
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.
Implementation
To successfully implement this search you need to be ingesting information on Web traffic that include fields relavent for traffic into the Web datamodel.
Known False Positives
False positives may be present with legitimate applications. Attempt to filter by dest IP or use Asset groups to restrict to servers.
Associated Analytic Story
Risk Based Analytics (RBA)
| Risk Message | Risk Score | Impact | Confidence |
|---|---|---|---|
| A suspicious URL has been requested against $dest$ by $src$, related to web shell activity. | 72 | 90 | 80 |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
References
Detection Testing
| Test Type | Status | Dataset | Source | Sourcetype |
|---|---|---|---|---|
| Validation | ✅ Passing | N/A | N/A | N/A |
| Unit | ✅ Passing | Dataset | /var/log/nginx/access.log |
nginx:plus:kv |
| Integration | ✅ Passing | Dataset | /var/log/nginx/access.log |
nginx:plus:kv |
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: 3