| ID | Technique | Tactic |
|---|---|---|
| T1105 | Ingress Tool Transfer | Command And Control |
| T1190 | Exploit Public-Facing Application | Initial Access |
| T1059 | Command and Scripting Interpreter | Execution |
| T1133 | External Remote Services | Initial Access |
Detection: Log4Shell CVE-2021-44228 Exploitation
Description
The following analytic identifies potential exploitation of Log4Shell CVE-2021-44228 by correlating multiple MITRE ATT&CK tactics detected in risk events. It leverages Splunk's risk data model to calculate the distinct count of MITRE ATT&CK tactics from Log4Shell-related detections. This activity is significant because it indicates a high probability of exploitation if two or more distinct tactics are observed. If confirmed malicious, this activity could lead to initial payload delivery, callback to a malicious server, and post-exploitation activities, potentially resulting in unauthorized access, lateral movement, and further compromise of the affected systems.
Search
1
2| tstats `security_content_summariesonly` min(_time) as firstTime max(_time) as lastTime sum(All_Risk.calculated_risk_score) as risk_score, count(All_Risk.calculated_risk_score) as risk_event_count, values(All_Risk.annotations.mitre_attack.mitre_tactic_id) as annotations.mitre_attack.mitre_tactic_id, dc(All_Risk.annotations.mitre_attack.mitre_tactic_id) as mitre_tactic_id_count, values(All_Risk.annotations.mitre_attack.mitre_technique_id) as annotations.mitre_attack.mitre_technique_id, dc(All_Risk.annotations.mitre_attack.mitre_technique_id) as mitre_technique_id_count, values(All_Risk.tag) as tag, values(source) as source, dc(source) as source_count from datamodel=Risk.All_Risk where All_Risk.analyticstories="Log4Shell CVE-2021-44228" All_Risk.risk_object_type="system" by All_Risk.risk_object All_Risk.risk_object_type All_Risk.annotations.mitre_attack.mitre_tactic
3| `drop_dm_object_name(All_Risk)`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| where source_count >= 2
7| `log4shell_cve_2021_44228_exploitation_filter`
Data Source
No data sources specified for this detection.
Macros Used
| Name | Value |
|---|---|
| security_content_ctime | convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
| log4shell_cve_2021_44228_exploitation_filter | search * |
log4shell_cve_2021_44228_exploitation_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.COMMAND_AND_CONTROL
KillChainPhase.DELIVERY
KillChainPhase.INSTALLATION
NistCategory.DE_AE
Cis18Value.CIS_10
APT-C-36
APT18
APT28
APT29
APT3
APT32
APT33
APT37
APT38
APT39
APT41
Ajax Security Team
Andariel
Aquatic Panda
BITTER
BRONZE BUTLER
BackdoorDiplomacy
Chimera
Cinnamon Tempest
Cobalt Group
Confucius
Daggerfly
Darkhotel
Dragonfly
Elderwood
Evilnum
FIN13
FIN7
FIN8
Fox Kitten
GALLIUM
Gamaredon Group
Gorgon Group
HAFNIUM
HEXANE
INC Ransom
IndigoZebra
Indrik Spider
Ke3chang
Kimsuky
Lazarus Group
LazyScripter
Leviathan
LuminousMoth
Magic Hound
Metador
Molerats
Moonstone Sleet
Moses Staff
MuddyWater
Mustang Panda
Mustard Tempest
Nomadic Octopus
OilRig
PLATINUM
Patchwork
Play
Rancor
Rocke
Sandworm Team
SideCopy
Sidewinder
Silence
TA2541
TA505
TA551
TeamTNT
Threat Group-3390
Tonto Team
Tropic Trooper
Turla
Volatile Cedar
Volt Typhoon
WIRTE
Whitefly
Windshift
Winnti Group
Winter Vivern
Wizard Spider
ZIRCONIUM
menuPass
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
APT19
APT32
APT37
APT39
Dragonfly
FIN5
FIN6
FIN7
Fox Kitten
Ke3chang
OilRig
Saint Bear
Stealth Falcon
Whitefly
Windigo
Winter Vivern
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 | False |
This configuration file applies to all detections of type Correlation. These correlations will generate Notable Events.
Implementation
To implement this correlation search a user needs to enable all detections in the Log4Shell Analytic Story and confirm it is generation risk events. A simple search index=risk analyticstories="Log4Shell CVE-2021-44228" should contain events.
Known False Positives
There are no known false positive for this search, but it could contain false positives as multiple detections can trigger and not have successful exploitation.
Associated Analytic Story
Risk Based Analytics (RBA)
| Risk Message | Risk Score | Impact | Confidence |
|---|---|---|---|
| Log4Shell Exploitation detected against $risk_object$. | 63 | 90 | 70 |
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 | log4shell |
stash |
| Integration | ✅ Passing | Dataset | log4shell |
stash |
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: 5