Potential DLL Sideloading Activity Via ExtExport.EXE

Status: test
Severity: medium
Log source: product windows, category process_creation
Author: frack113, Nasreddine Bencherchali (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects the execution of "Extexport.exe".A utility that is part of the Internet Explorer browser and is used to export and import various settings and data, particularly when switching between Internet Explorer and other web browsers like Firefox. It allows users to transfer bookmarks, browsing history, and other preferences from Internet Explorer to Firefox or vice versa. It can be abused as a tool to side load any DLL. If a folder is provided in the command line it'll load any DLL with one of the following names "mozcrt19.dll", "mozsqlite3.dll", or "sqlite.dll". Arbitrary DLLs can also be loaded if a specific number of flags was provided.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1218` System Binary Proxy Execution

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation

Rule body yaml

title: Potential DLL Sideloading Activity Via ExtExport.EXE
id: fb0b815b-f5f6-4f50-970f-ffe21f253f7a
status: test
description: |
    Detects the execution of "Extexport.exe".A utility that is part of the Internet Explorer browser and is used to export and import various settings and data, particularly when switching between Internet Explorer and other web browsers like Firefox. It allows users to transfer bookmarks, browsing history, and other preferences from Internet Explorer to Firefox or vice versa.
    It can be abused as a tool to side load any DLL. If a folder is provided in the command line it'll load any DLL with one of the following names "mozcrt19.dll", "mozsqlite3.dll", or "sqlite.dll".
    Arbitrary DLLs can also be loaded if a specific number of flags was provided.
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Extexport/
    - https://www.hexacorn.com/blog/2018/04/24/extexport-yet-another-lolbin/
    - https://www.microsoft.com/en-us/security/blog/2020/03/23/latest-astaroth-living-off-the-land-attacks-are-even-more-invisible-but-not-less-observable/
    - https://res.armor.com/resources/threat-intelligence/astaroth-banking-trojan/
    - https://securelist.com/the-tetrade-brazilian-banking-malware/97779/
    - https://www.welivesecurity.com/2020/03/05/guildma-devil-drives-electric/
author: frack113, Nasreddine Bencherchali (Nextron Systems)
date: 2021-11-26
modified: 2024-08-26
tags:
    - attack.stealth
    - attack.t1218
    - detection.threat-hunting
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        - Image|endswith: '\Extexport.exe'
        - OriginalFileName: 'extexport.exe'
    condition: selection
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    - Image|endswith: '\Extexport.exe'
    - OriginalFileName: 'extexport.exe'

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
`Image`	ends_with	`\Extexport.exe` corpus 3 (sigma 3)
`OriginalFileName`	eq	`extexport.exe`

`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 DLL Sideloading Activity Via ExtExport.EXE

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Indicators

Keyboard shortcuts

Search operators

Potential DLL Sideloading Activity Via ExtExport.EXE

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`