Query: Multiple failed authentications followed by Email Bombing
Matching 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)
Near-miss passage: T1498 Network Denial of Service. Tactics: impact. Description: Adversaries may perform Network Denial of Service (DoS) attacks to degrade or block the availability of targeted resources to users. Network DoS can be performed by exhausting the network bandwidth services rely on. Example resources include specific websites, email services, DNS, and web-based applications. Adversaries have been observed conducting network DoS attacks for political purposes(Citation: FireEye OpPoisonedHandover February 2016) and to support other malicious activities, including distraction(Citation: FSISAC FraudNetDoS September 2012), hacktivism, and extortion.(Citation: Symantec DDoS October 2014) A Network DoS will occur when the bandwidth capacity of the network connection to a system is exhausted due to the volume of malicious traffic directed at the resource or the network connections and network devices the resource relies on. For example, an adversary may send 10Gbps of traffic to a server that is hosted by a network with a 1Gbps connection to the internet. This traffic can be generated by a single system or multiple systems spread across the internet, which is commonly referred to as a distributed DoS (DDoS). To perform Network DoS attacks several aspects apply to multiple methods, including IP address spoofing, and botnets. Adversaries may use the original IP address of an attacking system, or spoof the source IP address to make the attack traffic more difficult to trace back to the attacking system or to enable reflection. This can increase the difficulty defenders have in defending against the attack by reducing or eliminating the effectiveness of filtering by the source address on network defense devices. For DoS attacks targeting the hosting system directly, see [Endpoint Denial of Service](https://attack.mitre.org/techniques/T1499).