Query: intelligence brief on T1587.004
Matching passage: T1587.004 Exploits. Tactics: resource development. Description: Adversaries may develop exploits that can be used during targeting. An exploit takes advantage of a bug or vulnerability in order to cause unintended or unanticipated behavior to occur on computer hardware or software. Rather than finding/modifying exploits from online or purchasing them from exploit vendors, an adversary may develop their own exploits.(Citation: NYTStuxnet) Adversaries may use information acquired via [Vulnerabilities](https://attack.mitre.org/techniques/T1588/006) to focus exploit development efforts. As part of the exploit development process, adversaries may uncover exploitable vulnerabilities through methods such as fuzzing and patch analysis.(Citation: Irongeek Sims BSides 2017) As with legitimate development efforts, different skill sets may be required for developing exploits. The skills needed may be located in-house, or may need to be contracted out. Use of a contractor may be considered an extension of that adversary's exploit development capabilities, provided the adversary plays a role in shaping requirements and maintains an initial degree of exclusivity to the exploit. Adversaries may use exploits during various phases of the adversary lifecycle (i.e. [Exploit Public-Facing Application](https://attack.mitre.org/techniques/T1190), [Exploitation for Client Execution](https://attack.mitre.org/techniques/T1203), [Exploitation for Privilege Escalation](https://attack.mitre.org/techniques/T1068), [Exploitation for Stealth](https://attack.mitre.org/techniques/T1211), [Exploitation for Credential Access](https://attack.mitre.org/techniques/T1212), [Exploitation of Remote Services](https://attack.mitre.org/techniques/T1210), and [Application or System Exploitation](https://attack.mitre.org/techniques/T1499/004)).
Near-miss passage: T1587.003 Digital Certificates. Tactics: resource development. Description: Adversaries may create self-signed SSL/TLS certificates that can be used during targeting. SSL/TLS certificates are designed to instill trust. They include information about the key, information about its owner's identity, and the digital signature of an entity that has verified the certificate's contents are correct. If the signature is valid, and the person examining the certificate trusts the signer, then they know they can use that key to communicate with its owner. In the case of self-signing, digital certificates will lack the element of trust associated with the signature of a third-party certificate authority (CA). Adversaries may create self-signed SSL/TLS certificates that can be used to further their operations, such as encrypting C2 traffic (ex: [Asymmetric Cryptography](https://attack.mitre.org/techniques/T1573/002) with [Web Protocols](https://attack.mitre.org/techniques/T1071/001)) or even enabling [Adversary-in-the-Middle](https://attack.mitre.org/techniques/T1557) if added to the root of trust (i.e. [Install Root Certificate](https://attack.mitre.org/techniques/T1553/004)). After creating a digital certificate, an adversary may then install that certificate (see [Install Digital Certificate](https://attack.mitre.org/techniques/T1608/003)) on infrastructure under their control.