Esentutl Steals Browser Information

Severity: medium
Author: frack113
Source: upstream

One way Qbot steals sensitive information is by extracting browser data from Internet Explorer and Microsoft Edge by using the built-in utility esentutl.exe

MITRE ATT&CK coverage

Tactic	Techniques
Collection	`T1005` Data from Local System

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
Image|endswith: '\esentutl.exe'
OriginalFileName: esentutl.exe

Stage 2: `all of selection_flag`

CommandLine|contains: -r

Stage 3: `all of selection_webcache`

CommandLine|contains: '\Windows\WebCache'

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	`-r` corpus 3 (sigma 3) `\Windows\WebCache`
`Image`	ends_with	`\esentutl.exe` corpus 8 (sigma 8)
`OriginalFileName`	eq	`esentutl.exe` corpus 2 (sigma 2)