Query: SIEM correlation: initial access activity consistent with Content Injection
Matching passage: T1659 Content Injection. Tactics: initial access, command and control. Description: Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic. Rather than luring victims to malicious payloads hosted on a compromised website (i.e., [Drive-by Target](https://attack.mitre.org/techniques/T1608/004) followed by [Drive-by Compromise](https://attack.mitre.org/techniques/T1189)), adversaries may initially access victims through compromised data-transfer channels where they can manipulate traffic and/or inject their own content. These compromised online network channels may also be used to deliver additional payloads (i.e., [Ingress Tool Transfer](https://attack.mitre.org/techniques/T1105)) and other data to already compromised systems.(Citation: ESET MoustachedBouncer) Adversaries may inject content to victim systems in various ways, including: * From the middle, where the adversary is in-between legitimate online client-server communications (**Note:** this is similar but distinct from [Adversary-in-the-Middle](https://attack.mitre.org/techniques/T1557), which describes AiTM activity solely within an enterprise environment) (Citation: Kaspersky Encyclopedia MiTM) * From the side, where malicious content is injected and races to the client as a fake response to requests of a legitimate online server (Citation: Kaspersky ManOnTheSide) Content injection is often the result of compromised upstream communication channels, for example at the level of an internet service provider (ISP) as is the case with "lawful interception."(Citation: Kaspersky ManOnTheSide)(Citation: ESET MoustachedBouncer)(Citation: EFF China GitHub Attack)
Near-miss passage: T1568.002 Domain Generation Algorithms. Tactics: command and control. Description: Adversaries may make use of Domain Generation Algorithms (DGAs) to dynamically identify a destination domain for command and control traffic rather than relying on a list of static IP addresses or domains. This has the advantage of making it much harder for defenders to block, track, or take over the command and control channel, as there potentially could be thousands of domains that malware can check for instructions.(Citation: Cybereason Dissecting DGAs)(Citation: Cisco Umbrella DGA)(Citation: Unit 42 DGA Feb 2019) DGAs can take the form of apparently random or “gibberish” strings (ex: istgmxdejdnxuyla.ru) when they construct domain names by generating each letter. Alternatively, some DGAs employ whole words as the unit by concatenating words together instead of letters (ex: cityjulydish.net). Many DGAs are time-based, generating a different domain for each time period (hourly, daily, monthly, etc). Others incorporate a seed value as well to make predicting future domains more difficult for defenders.(Citation: Cybereason Dissecting DGAs)(Citation: Cisco Umbrella DGA)(Citation: Talos CCleanup 2017)(Citation: Akamai DGA Mitigation) Adversaries may use DGAs for the purpose of [Fallback Channels](https://attack.mitre.org/techniques/T1008). When contact is lost with the primary command and control server malware may employ a DGA as a means to reestablishing command and control.(Citation: Talos CCleanup 2017)(Citation: FireEye POSHSPY April 2017)(Citation: ESET Sednit 2017 Activity)