Potential Windows Defender AV Bypass Via Dump64.EXE Rename

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

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	Title
Sysmon	Event ID 1	Process creation

Rule body yaml

title: Potential Windows Defender AV Bypass Via Dump64.EXE Rename
id: 129966c9-de17-4334-a123-8b58172e664d
status: test
description: |
    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.
references:
    - https://twitter.com/mrd0x/status/1460597833917251595
author: Austin Songer @austinsonger, Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2021-11-26
modified: 2024-06-21
tags:
    - attack.credential-access
    - attack.t1003.001
logsource:
    product: windows
    category: process_creation
detection:
    selection_dump:
        Image|startswith: ':\Program Files'
        Image|contains: '\Microsoft Visual Studio\'
        Image|endswith: '\dump64.exe'
    selection_tools_procdump:
        - OriginalFileName: 'procdump'
        - CommandLine|contains:
              - ' -ma ' # Full Dump
              - ' -mp ' # Mini Plus
    condition: selection_dump and 1 of selection_tools_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection_dump and 1 of selection_tools_*

Stage 1: `selection_dump`

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

Stage 2: `selection_tools_procdump`

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

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 5 (sigma 4, chronicle 1) `-mp` corpus 3 (sigma 3)
`Image`	ends_with	`\dump64.exe` corpus 2 (sigma 2)
`Image`	match	`\Microsoft Visual Studio\`
`Image`	starts_with	`:\Program Files`
`OriginalFileName`	eq	`procdump` corpus 4 (sigma 2, elastic 1, splunk 1)

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Potential Windows Defender AV Bypass Via Dump64.EXE Rename

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_dump`

Stage 2: `selection_tools_procdump`

Indicators

Keyboard shortcuts

Search operators

Potential Windows Defender AV Bypass Via Dump64.EXE Rename

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_dump

Stage 2: selection_tools_procdump

Indicators

Stage 0: `condition`

Stage 1: `selection_dump`

Stage 2: `selection_tools_procdump`