Potentially Suspicious DLL Registered Via Odbcconf.EXE

Status: test
Severity: high
Log source: category process_creation, product windows
Author: Nasreddine Bencherchali (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects execution of "odbcconf" with the "REGSVR" action where the DLL in question doesn't contain a ".dll" extension. Which is often used as a method to evade defenses.

Known false positives

Unlikely

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1218.008` System Binary Proxy Execution: Odbcconf

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: Potentially Suspicious DLL Registered Via Odbcconf.EXE
id: ba4cfc11-d0fa-4d94-bf20-7c332c412e76
related:
    - id: 9f0a8bf3-a65b-440a-8c1e-5cb1547c8e70
      type: derived
status: test
description: Detects execution of "odbcconf" with the "REGSVR" action where the DLL in question doesn't contain a ".dll" extension. Which is often used as a method to evade defenses.
references:
    - https://learn.microsoft.com/en-us/sql/odbc/odbcconf-exe?view=sql-server-ver16
    - https://lolbas-project.github.io/lolbas/Binaries/Odbcconf/
    - https://www.trendmicro.com/en_us/research/17/h/backdoor-carrying-emails-set-sights-on-russian-speaking-businesses.html
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-22
tags:
    - attack.stealth
    - attack.t1218.008
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\odbcconf.exe'
        - OriginalFileName: 'odbcconf.exe'
    selection_cli:
        # Note: The "/A" flag is not required to call a specific action
        CommandLine|contains: 'REGSVR '
    filter_main_dll_ext:
        CommandLine|contains: '.dll'
    condition: all of selection_* and not 1 of filter_main_*
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: `condition`

all of selection_* and not 1 of filter_main_*

Stage 1: `selection_img`

selection_img:
    - Image|endswith: '\odbcconf.exe'
    - OriginalFileName: 'odbcconf.exe'

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains: 'REGSVR '

Stage 3: `not filter_main_dll_ext`

filter_main_dll_ext:
    CommandLine|contains: '.dll'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`CommandLine`	match	`.dll`	`excludes:CommandLine` `field:"CommandLine" value:".dll"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`REGSVR` corpus 2 (sigma 2)	`field:"CommandLine" kind:match value:"REGSVR "`
`Image`	ends_with	`\odbcconf.exe` corpus 11 (sigma 11)	`field:"Image" kind:ends_with value:"\odbcconf.exe"`
`OriginalFileName`	eq	`odbcconf.exe` corpus 12 (sigma 9, elastic 3)	`field:"OriginalFileName" kind:eq value:"odbcconf.exe"`