Query: how to detect Acquire Access
Matching passage: T1650 Acquire Access. Tactics: resource development. Description: Adversaries may purchase or otherwise acquire an existing access to a target system or network. A variety of online services and initial access broker networks are available to sell access to previously compromised systems.(Citation: Microsoft Ransomware as a Service)(Citation: CrowdStrike Access Brokers)(Citation: Krebs Access Brokers Fortune 500) In some cases, adversary groups may form partnerships to share compromised systems with each other.(Citation: CISA Karakurt 2022) Footholds to compromised systems may take a variety of forms, such as access to planted backdoors (e.g., [Web Shell](https://attack.mitre.org/techniques/T1505/003)) or established access via [External Remote Services](https://attack.mitre.org/techniques/T1133). In some cases, access brokers will implant compromised systems with a “load” that can be used to install additional malware for paying customers.(Citation: Microsoft Ransomware as a Service) By leveraging existing access broker networks rather than developing or obtaining their own initial access capabilities, an adversary can potentially reduce the resources required to gain a foothold on a target network and focus their efforts on later stages of compromise. Adversaries may prioritize acquiring access to systems that have been determined to lack security monitoring or that have high privileges, or systems that belong to organizations in a particular sector.(Citation: Microsoft Ransomware as a Service)(Citation: CrowdStrike Access Brokers) In some cases, purchasing access to an organization in sectors such as IT contracting, software development, or telecommunications may allow an adversary to compromise additional victims via a [Trusted Relationship](https://attack.mitre.org/techniques/T1199), [Multi-Factor Authentication Interception](https://attack.mitre.org/techniques/T1111), or even [Supply Chain Compromise](https://attack.mitre.org/techniques/T1195). **Note:** while this technique is distinct from other behaviors such as [Purchase
Near-miss passage: T1588.004 Digital Certificates. Tactics: resource development. Description: Adversaries may buy and/or steal 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. Adversaries may purchase or steal SSL/TLS certificates 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 the certificate is trusted or otherwise added to the root of trust (i.e. [Install Root Certificate](https://attack.mitre.org/techniques/T1553/004)). The purchase of digital certificates may be done using a front organization or using information stolen from a previously compromised entity that allows the adversary to validate to a certificate provider as that entity. Adversaries may also steal certificate materials directly from a compromised third-party, including from certificate authorities.(Citation: DiginotarCompromise) Adversaries may register or hijack domains that they will later purchase an SSL/TLS certificate for. Certificate authorities exist that allow adversaries to acquire SSL/TLS certificates, such as domain validation certificates, for free.(Citation: Let's Encrypt FAQ) After obtaining 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.