Query: SIEM correlation: impact activity consistent with Data Encrypted for Impact
Matching passage: T1486 Data Encrypted for Impact. Tactics: impact. Description: Adversaries may encrypt data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources. They can attempt to render stored data inaccessible by encrypting files or data on local and remote drives and withholding access to a decryption key. This may be done in order to extract monetary compensation from a victim in exchange for decryption or a decryption key (ransomware) or to render data permanently inaccessible in cases where the key is not saved or transmitted.(Citation: US-CERT Ransomware 2016)(Citation: FireEye WannaCry 2017)(Citation: US-CERT NotPetya 2017)(Citation: US-CERT SamSam 2018) In the case of ransomware, it is typical that common user files like Office documents, PDFs, images, videos, audio, text, and source code files will be encrypted (and often renamed and/or tagged with specific file markers). Adversaries may need to first employ other behaviors, such as [File and Directory Permissions Modification](https://attack.mitre.org/techniques/T1222) or [System Shutdown/Reboot](https://attack.mitre.org/techniques/T1529), in order to unlock and/or gain access to manipulate these files.(Citation: CarbonBlack Conti July 2020) In some cases, adversaries may encrypt critical system files, disk partitions, and the MBR.(Citation: US-CERT NotPetya 2017) Adversaries may also encrypt virtual machines hosted on ESXi or other hypervisors.(Citation: Crowdstrike Hypervisor Jackpotting Pt 2 2021) To maximize impact on the target organization, malware designed for encrypting data may have worm-like features to propagate across a network by leveraging other attack techniques like [Valid Accounts](https://attack.mitre.org/techniques/T1078), [OS Credential Dumping](https://attack.mitre.org/techniques/T1003), and [SMB/Windows Admin Shares](https://attack.mitre.org/techniques/T1021/002).(Citation: FireEye WannaCry 2017)(Citation: US-CERT NotPetya 2017) Encryption malware may also leverage [Internal Defacement](https:
Near-miss passage: T1667 Email Bombing. Tactics: impact. Description: Adversaries may flood targeted email addresses with an overwhelming volume of messages. This may bury legitimate emails in a flood of spam and disrupt business operations.(Citation: sophos-bombing)(Citation: krebs-email-bombing) An adversary may accomplish email bombing by leveraging an automated bot to register a targeted address for e-mail lists that do not validate new signups, such as online newsletters. The result can be a wave of thousands of e-mails that effectively overloads the victim’s inbox.(Citation: krebs-email-bombing)(Citation: hhs-email-bombing) By sending hundreds or thousands of e-mails in quick succession, adversaries may successfully divert attention away from and bury legitimate messages including security alerts, daily business processes like help desk tickets and client correspondence, or ongoing scams.(Citation: hhs-email-bombing) This behavior can also be used as a tool of harassment.(Citation: krebs-email-bombing) This behavior may be a precursor for [Spearphishing Voice](https://attack.mitre.org/techniques/T1566/004). For example, an adversary may email bomb a target and then follow up with a phone call to fraudulently offer assistance. This social engineering may lead to the use of [Remote Access Software](https://attack.mitre.org/techniques/T1663) to steal credentials, deploy ransomware, conduct [Financial Theft](https://attack.mitre.org/techniques/T1657)(Citation: sophos-bombing), or engage in other malicious activity.(Citation: rapid7-email-bombing)