﻿---
title: Unsigned DLL Loaded by a Trusted Process
description: Identifies digitally signed (trusted) processes loading unsigned DLLs. Attackers may plant their payloads into the application folder and invoke the legitimate...
url: https://www.elastic.co/elastic/docs-builder/docs/2666/reference/security/prebuilt-rules/rules_building_block/defense_evasion_dll_hijack
products:
  - Elastic Security
---

# Unsigned DLL Loaded by a Trusted Process
Identifies digitally signed (trusted) processes loading unsigned DLLs. Attackers may plant their payloads into the
application folder and invoke the legitimate application to execute the payload, masking actions they perform under a
legitimate, trusted, and potentially elevated system or software process.
**Rule type**: eql
**Rule indices**:
- logs-endpoint.events.library-*

**Rule Severity**: low
**Risk Score**: 21
**Runs every**: 60m
**Searches indices from**: `now-119m`
**Maximum alerts per execution**: 100
**References**:
**Tags**:
- Domain: Endpoint
- OS: Windows
- Use Case: Threat Detection
- Tactic: Defense Evasion
- Rule Type: BBR
- Data Source: Elastic Defend

**Version**: 106
**Rule authors**:
- Elastic

**Rule license**: Elastic License v2

## Rule Query

```eql
library where host.os.type == "windows" and
   (dll.Ext.relative_file_creation_time <= 500 or
    dll.Ext.relative_file_name_modify_time <= 500 or
    dll.Ext.device.product_id : ("Virtual DVD-ROM", "Virtual Disk")) and dll.hash.sha256 != null and
    process.code_signature.status :"trusted" and not dll.code_signature.status : ("trusted", "errorExpired", "errorCode_endpoint*") and
    /* DLL loaded from the process.executable current directory */
    endswith~(substring(dll.path, 0, length(dll.path) - (length(dll.name) + 1)), substring(process.executable, 0, length(process.executable) - (length(process.name) + 1)))
    and not user.id : "S-1-5-18" and
    not dll.hash.sha256 : (
        "19588e6a318894abe8094374bee233e666f319de909c69f12a6047b14473e299",
        "6e8bee250c8cc1b65150522f33794759f5c65f58fff17c5cbf6422ad68b421d2",
        "55de11531dc0e566cb91f26e48d1301a161a4b8b24abed42304d711412368760",
        "56a5148d00c2d9e58415be2d64eca922a58063fe26d9af1c87084aa383c9058e",
        "83ee0ff920144edb2c2f4ea10130f55443493290886985a63233fa2431e450f9",
        "0d0d8f2eaff6b5f75e63d9721d5a0480b30e70792fe0d3a24d76fd3e61b05982",
        "8b6ce3a640e2d6f36b0001be2a1abb765ae51e62c314a15911e75138cbb544bb",
        "ea02a19dd824cb7d611b8821d1b9e6a076714a195d027d1ff918128a64ac5220",
        "02a6d001e6dd944738e09b720e49dcb1272cb782b870e5ae319d4600bc192225",
        "e7714a1d6ac3f4c4ae22564b9ca301e486f5f42691859c0a687246c47b5cf5c9",
        "17f0f709fb7f6190c03b19b6198fd863b6f0d79f46ccfebac6064be747a4cb3e",
        "cb7ab3788d10940df874acd97b1821bbb5ee4a91f3eec11982bb5bf7a3c96443",
        "c944ee510721a1d30d42227cc3061dfdcbc144c952381afcfe4f6e82c5435ffc",
        "967189adfbc889fde89aafc867f7a1f02731f8592cf6fd5a4ace1929213e2e13",
        "4a824526749790603eb66777f79787128dd282162a3904a4c1135de43b14d029",
        "620a7e658af05cc848091b8a639854b9b15700a9061b4a3d078523653133a4af",
        "cb220267fb0116b298bab6a09a764420d630c52026f7d750f8ffca4818389327",
        "0da1f856d92d6b95f10ed8c3f629cd15468c906de9352fb4ae629139d1412eed",
        "e1646c7778c24407a17881908037a49ecfcb5a980d155212d544302653a3ef62",
        "e102c9c5b22ceb60dc516ab4124bea8ec8e808b08eec48ea7ac674d13fca82ef",
        "c7544e1f9927afdf6e8cd7063020b572e60fe8f00af39227eb831d331df38225",
        "3668c6749db59a6cbc5293d0a4f904f76d6fb5048704449dd53894916f408a57",
        "7705851ba047a8154402aca92621b60be0e0e9d9b52b19bf8be540305bd53dba",
        "b5acf358ff97127eac9ef4c664a980b937376b5295ef23d77ee338225de10d60",
        "394d2d862f2ddce71f28d9b933b21a7d6c621c80ef28652574f758f77f01f716",
        "e958d03db79e9f1d2770c70a5bc24904aa3e2d27a8d5637684cf8166b38908f2",
        "284701380f33a30b25e8eb9822e7f47179238e91d08bd3fb5a117145de7e0d8d",
        "497471497886f18ca16f7facab7d76dc9bfadd69deb9c6e4ea9bdc0869a15628",
        "739bedcfc8eb860927eb2057474be5b39518aaaa6703f9f85307a432fa1f236e",
        "8f4c72e3c7de1ab5d894ec7813f65c5298ecafc183f31924b44a427433ffca42",
        "1ac4753056179b358132c55ca3086d550849ae30259ba94f334826c2fbf6c57e",
        "53e8fecd7d4b1b74064eba9bfa6a361d52929f440954931b4ba65615148bf0ea",
        "e9088afd8871dbad5eda47a9d8abf3b08dd2e17c423ba8a05f9b6ad6751f9b7c",
        "ab27eb05130db2f92499234b69ff97ee6429c7824efcb7324ae3e404e2b405bf",
        "553451008520a5f0110d84192cba40208fb001c27454f946e85e6fb2e6553292"
    )
```

**Framework:** MITRE ATT&CK
- Tactic:
  - Name: Defense Evasion
- Id: TA0005
- Reference URL: [[https://attack.mitre.org/tactics/TA0005/](https://attack.mitre.org/tactics/TA0005/)](https://attack.mitre.org/tactics/TA0005/)
- Technique:
  - Name: Hijack Execution Flow
- Id: T1574
- Reference URL: [[https://attack.mitre.org/techniques/T1574/](https://attack.mitre.org/techniques/T1574/)](https://attack.mitre.org/techniques/T1574/)
- Sub Technique:
  - Name: DLL
- Id: T1574.001
- Reference URL: [[https://attack.mitre.org/techniques/T1574/001/](https://attack.mitre.org/techniques/T1574/001/)](https://attack.mitre.org/techniques/T1574/001/)
- Sub Technique:
  - Name: DLL
- Id: T1574.001
- Reference URL: [[https://attack.mitre.org/techniques/T1574/001/](https://attack.mitre.org/techniques/T1574/001/)](https://attack.mitre.org/techniques/T1574/001/)