Suspicious File Execution From Internet Hosted WebDav Share

Severity: high
Author: pH-T (Nextron Systems)
Source: upstream

Detects the execution of the "net use" command to mount a WebDAV server and then immediately execute some content in it. As seen being used in malicious LNK files

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.001` Command and Scripting Interpreter: PowerShell

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
Image|contains: '\cmd.exe'
OriginalFileName: Cmd.EXE

Stage 2: `all of selection_base`

CommandLine|contains: ' net use http'
CommandLine|contains: '& start /b '
CommandLine|contains: '\DavWWWRoot\'

Stage 3: `all of selection_ext`

or:
CommandLine|contains: '.bat '
CommandLine|contains: '.dll '
CommandLine|contains: '.exe '
CommandLine|contains: '.ps1 '
CommandLine|contains: '.vbs '

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`CommandLine`	match	`net use http` `& start /b` `.bat` `.dll` corpus 2 (sigma 2) `.exe` `.ps1` `.vbs` `\DavWWWRoot\` corpus 2 (sigma 2)
`Image`	match	`\cmd.exe`
`OriginalFileName`	eq	`Cmd.EXE` corpus 2 (sigma 2)