Query: SIEM correlation: persistence activity consistent with Cloud Application Integration
Matching passage: T1671 Cloud Application Integration. Tactics: persistence. Description: Adversaries may achieve persistence by leveraging OAuth application integrations in a software-as-a-service environment. Adversaries may create a custom application, add a legitimate application into the environment, or even co-opt an existing integration to achieve malicious ends.(Citation: Push Security SaaS Persistence 2022)(Citation: SaaS Attacks GitHub Evil Twin Integrations) OAuth is an open standard that allows users to authorize applications to access their information on their behalf. In a SaaS environment such as Microsoft 365 or Google Workspace, users may integrate applications to improve their workflow and achieve tasks. Leveraging application integrations may allow adversaries to persist in an environment – for example, by granting consent to an application from a high-privileged adversary-controlled account in order to maintain access to its data, even in the event of losing access to the account.(Citation: Wiz Midnight Blizzard 2024)(Citation: Microsoft Malicious OAuth Applications 2022)(Citation: Huntress Persistence Microsoft 365 Compromise 2024) In some cases, integrations may remain valid even after the original consenting user account is disabled.(Citation: Push Security Slack Persistence 2023) Application integrations may also allow adversaries to bypass multi-factor authentication requirements through the use of [Application Access Token](https://attack.mitre.org/techniques/T1550/001)s. Finally, they may enable persistent [Automated Exfiltration](https://attack.mitre.org/techniques/T1020) over time.(Citation: Synes Cyber Corner Malicious Azure Application 2023) Creating or adding a new application may require the adversary to create a dedicated [Cloud Account](https://attack.mitre.org/techniques/T1136/003) for the application and assign it [Additional Cloud Roles](https://attack.mitre.org/techniques/T1098/003) – for example, in Microsoft 365 environments, an application can only access resources via an associated service principal.(Citation: M
Near-miss passage: T1505.002 Transport Agent. Tactics: persistence. Description: Adversaries may abuse Microsoft transport agents to establish persistent access to systems. Microsoft Exchange transport agents can operate on email messages passing through the transport pipeline to perform various tasks such as filtering spam, filtering malicious attachments, journaling, or adding a corporate signature to the end of all outgoing emails.(Citation: Microsoft TransportAgent Jun 2016)(Citation: ESET LightNeuron May 2019) Transport agents can be written by application developers and then compiled to .NET assemblies that are subsequently registered with the Exchange server. Transport agents will be invoked during a specified stage of email processing and carry out developer defined tasks. Adversaries may register a malicious transport agent to provide a persistence mechanism in Exchange Server that can be triggered by adversary-specified email events.(Citation: ESET LightNeuron May 2019) Though a malicious transport agent may be invoked for all emails passing through the Exchange transport pipeline, the agent can be configured to only carry out specific tasks in response to adversary defined criteria. For example, the transport agent may only carry out an action like copying in-transit attachments and saving them for later exfiltration if the recipient email address matches an entry on a list provided by the adversary.