# T1203 - Exploitation for Client Execution

## SOC Recommendation
Investigate Exploitation for Client Execution activity in the context of Execution: confirm scope, affected host/identity, and whether it matches expected administrative behaviour before deciding this is benign.

## D3FEND Mappings
| D3FEND Technique | Relationship | Practical SOC Action |
|---|---|---|
| Memory Boundary Tracking | Detect | Monitor for Memory Boundary Tracking indicators relevant to this technique. |
| Process Segment Execution Prevention | Harden | Apply Process Segment Execution Prevention to reduce this technique's viability before an incident occurs. |

## Investigation Steps
1. Review Defender for Endpoint / Defender XDR alerts and timeline for the affected host or identity.
2. Check Sentinel analytics rules and incidents correlated with this technique.
3. Review Entra ID sign-in and audit logs if the technique involves an identity or cloud resource.

## Evidence to Collect
- Host or resource affected
- Account or identity involved
- Timestamp of the activity
- Related process, file, or network artifact
- Any preceding or follow-on alerts

## Response Actions
| Action | Risk | Automation Safe | Approval Required |
|---|---|---|---|
| Contain the affected host or account | Medium | No | Yes |
| Collect and preserve evidence | Low | Yes | No |

## KQL
```kql
let Threshold = 1;  
 AzureDiagnostics
 | where Category == "ApplicationGatewayFirewallLog"
 | where action_s == "Matched"
 | project transactionId_g, hostname_s, requestUri_s, TimeGenerated, clientIp_s, Message, details_message_s, details_data_s
 | join kind = inner(
 AzureDiagnostics
 | where Category == "ApplicationGatewayFirewallLog"
 | where action_s == "Blocked"
 | parse Message with MessageText 'Total Inbound Score: ' TotalInboundScore ' - SQLI=' SQLI_Score ',XSS=' XSS_Score ',RFI=' RFI_Score ',LFI=' LFI_Score ',RCE=' RCE_Score ',PHPI=' PHPI_Score ',HTTP=' HTTP_Score ',SESS=' SESS_Score '): ' Blocked_Reason '; individual paranoia level scores:' Paranoia_Score
 | where Blocked_Reason contains "XSS" and toint(TotalInboundScore) >=15 and toint(XSS_Score) >= 10 and toint(SQLI_Score) <= 5) on transactionId_g
 | extend Uri = strcat(hostname_s,requestUri_s)
 | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), TransactionID = make_set(transactionId_g), Message = make_set(Message), Detail_Message = make_set(details_message_s), Detail_Data = make_set(details_data_s), Total_TransactionId = dcount(transactionId_g) by clientIp_s, Uri, action_s, SQLI_Score, XSS_Score, TotalInboundScore
 | where Total_TransactionId >= Threshold
```
```kql
let sha256Hashes = dynamic(["5dd1ca0d471dee41eb3ea0b6ea117810f228354fc3b7b47400a812573d40d91d", "5fc44c7342b84f50f24758e39c8848b2f0991e8817ef5465844f5f2ff6085a57", "6cff0bbd62efe99f381e5cc0c4182b0fb7a9a34e4be9ce68ee6b0d0ea3eee39c"]);
let signames = dynamic(["Ransom:Win32/Prestige"]);
(union isfuzzy=true
(CommonSecurityLog
| where FileHash in (sha256Hashes)
| project TimeGenerated, Message, SourceUserID, FileHash, Type
| extend timestamp = TimeGenerated, Algorithm = "SHA256", AccountNTName = SourceUserID
),
(imFileEvent
| where TargetFileSHA256 has_any (sha256Hashes)
| extend AccountNT = ActorUsername, Computer = DvcHostname, IPAddress = SrcIpAddr, CommandLine = ActingProcessCommandLine, FileHash = TargetFileSHA256
| project Type, TimeGenerated, Computer, AccountNT, IPAddress, CommandLine, FileHash, Algorithm = "SHA256"
),
(Event
| where Source =~ "Microsoft-Windows-Sysmon"
| where EventID == 1
| extend EvData = parse_xml(EventData)
| extend EventDetail = EvData.DataItem.EventData.Data
| extend ProcessId = tolong(EventDetail.[3].["#text"]), Image = tostring(EventDetail.[4].["#text"]), CommandLine = tostring(EventDetail.[10].["#text"]), Hashes = tostring(EventDetail.[17].["#text"])
| extend Hashes = extract_all(@"(?P<key>\w+)=(?P<value>[a-zA-Z0-9]+)", dynamic(["key","value"]), Hashes)
| extend Hashes = column_ifexists("Hashes", dynamic(["", ""])), CommandLine = column_ifexists("CommandLine", "")
| mv-expand Hashes
| where Hashes[0] =~ "SHA256" and Hashes[1] has_any (sha256Hashes)  
| project TimeGenerated, EventDetail, UserName, Computer, Type, Source, ProcessId, Hashes, CommandLine, Image
| extend Type = strcat(Type, ": ", Source)
| extend AccountNT = UserName, InitiatingProcessId = ProcessId
| extend Process = tostring(split(Image, '\\', -1)[-1]), Algorithm = "SHA256", FileHash = tostring(Hashes[1]) 
),
(DeviceEvents
| where InitiatingProcessSHA256 has_any (sha256Hashes) or SHA256 has_any (sha256Hashes)
| project TimeGenerated, ActionType, DeviceId, DeviceName, InitiatingProcessAccountDomain, InitiatingProcessAccountName, InitiatingProcessCommandLine, InitiatingProcessFolderPath, InitiatingProcessId, InitiatingProcessParentFileName, InitiatingProcessFileName, InitiatingProcessSHA256, Type
| extend AccountNT = InitiatingProcessAccountName, Computer = DeviceName
| extend Algorithm = "SHA256", FileHash = tostring(InitiatingProcessSHA256), CommandLine = InitiatingProcessCommandLine, Image = InitiatingProcessFolderPath
),
(DeviceFileEvents
| where SHA256 has_any (sha256Hashes)
| project TimeGenerated, ActionType, DeviceId, DeviceName, InitiatingProcessAccountDomain, InitiatingProcessAccountName, InitiatingProcessCommandLine, InitiatingProcessFolderPath, InitiatingProcessId, InitiatingProcessParentFileName, InitiatingProcessFileName, InitiatingProcessSHA256, Type
| extend AccountNT = InitiatingProcessAccountName, Computer = DeviceName
| extend Algorithm = "SHA256", FileHash = tostring(InitiatingProcessSHA256), CommandLine = InitiatingProcessCommandLine, Image = InitiatingProcessFolderPath
),
(DeviceImageLoadEvents
| where SHA256 has_any (sha256Hashes)
| project TimeGenerated, ActionType, DeviceId, DeviceName, InitiatingProcessAccountDomain, InitiatingProcessAccountName, InitiatingProcessCommandLine, InitiatingProcessFolderPath, InitiatingProcessId, InitiatingProcessParentFileName, InitiatingProcessFileName, InitiatingProcessSHA256, Type
| extend AccountNT = InitiatingProcessAccountName, Computer = DeviceName
| extend Algorithm = "SHA256", FileHash = tostring(InitiatingProcessSHA256), CommandLine = InitiatingProcessCommandLine, Image = InitiatingProcessFolderPath
),
(SecurityAlert
| where ProductName == "Microsoft Defender Advanced Threat Protection"
| extend ThreatName = tostring(parse_json(ExtendedProperties).ThreatName)
| where isnotempty(ThreatName)
| where ThreatName has_any (signames)
| extend Computer = tostring(parse_json(Entities)[0].HostName)
)
)
| extend AccountNTName = tostring(split(AccountNT, "\\")[0]), AccountNTDomain = tostring(split(AccountNT, "\\")[1])
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| project-away DomainIndex
```
```kql
SecurityNestedRecommendation
| where RemediationDescription has 'CVE-2021-38647'
| parse ResourceDetails with * 'virtualMachines/' VirtualMAchine '"' *
| summarize arg_min(TimeGenerated, *) by TenantId, RecommendationSubscriptionId, VirtualMAchine, RecommendationName,Description,RemediationDescription, tostring(AdditionalData),VulnerabilityId
| extend HostName = tostring(split(VirtualMAchine, ".")[0]), DomainIndex = toint(indexof(VirtualMAchine, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(VirtualMAchine, DomainIndex + 1), VirtualMAchine)
```

## Escalation Criteria
- Exploitation for Client Execution activity observed on a privileged account or critical system.
- Activity follows or precedes other suspicious behaviour in the same investigation.
- Automated triage cannot confidently rule out malicious intent.

## False Positive Considerations
- Legitimate administrative or maintenance activity matching this pattern.
- Approved security testing or red team exercise.
- Known benign software producing similar telemetry.

Generated by SOC Response Atlas by Basyrix.