has gained access through compromised accounts at cloud solution partners and used compromised certificates issued by Mimecast to authenticate to Mimecast customer systems.(Citation: Cybersecurity Advisory SVR TTP May 2021)(Citation: CrowdStrike StellarParticle January 2022)
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request. ### Instruction: List the MITRE techniques contained in the text. ### Input: has gained access through compromised accounts at cloud solution partners and used compromised certificates issued by Mimecast to authenticate to Mimecast customer systems.(Citation: Cybersecurity Advisory SVR TTP May 2021)(Citation: CrowdStrike StellarParticle January 2022) ### Response: T1199.