Potential Windows Defender AV Bypass Via Dump64.EXE Rename

Severity: high
Author: Austin Songer @austinsonger, Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
Source: upstream

Detects when a user is potentially trying to bypass the Windows Defender AV by renaming a tool to dump64.exe and placing it in the Visual Studio folder. Currently the rule is covering only usage of procdump but other utilities can be added in order to increase coverage.

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1003.001` OS Credential Dumping: LSASS Memory

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `selection_dump`

Image|endswith: '\dump64.exe'
Image|contains: '\Microsoft Visual Studio\'
Image|startswith: ':\Program Files'

Stage 2: `1 of selection_tools_procdump`

or:
CommandLine|contains: ' -ma '
CommandLine|contains: ' -mp '
OriginalFileName: procdump

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	`-ma` corpus 4 (sigma 4) `-mp` corpus 3 (sigma 3)
`Image`	ends_with	`\dump64.exe` corpus 2 (sigma 2)
`Image`	match	`\Microsoft Visual Studio\` corpus 2 (sigma 2)
`Image`	starts_with	`:\Program Files`
`OriginalFileName`	eq	`procdump` corpus 2 (sigma 2)