电子邮件轰炸(Email bombing)是一种互联网滥用形式，其中大量相同的电子邮件被发送到特定的电子邮件地址以影响计算机的操作系统。当邮箱被无数不需要的电子邮件淹没时，它的容量就会耗尽，导致无法接收更多的电子邮件。这样做可以防止受害者收到或注意到他们邮件中的一些其他重要消息。缓慢的系统或无法发送或接收电子邮件可能是电子邮件被轰炸的迹象。发生这种情况是因为系统已经忙于处理无数的电子邮件。
电子邮件轰炸和垃圾邮件
邮件轰炸有三种方法：群发(Mass)邮件、列表(List)链接和ZIP轰炸。群发邮件(Mass mailing)涉及向同一地址发送多封重复的电子邮件，但很容易被垃圾邮件过滤器检测到。第二个，列表链接(List linking)，涉及将目标电子邮件地址订阅到不同的电子邮件列表订阅。用户将始终从所有这些订阅中收到垃圾邮件，并且必须分别手动取消订阅每个列表。使用包含数百万和数十亿字符的ZIP存档附件完成的(ZIP)电子邮件(Email)轰炸称为ZIP 轰炸(ZIP bombing). 使用防病毒软件检查邮件的邮件服务器需要更大的处理能力，可能导致拒绝服务(Denial of Service)。
虽然您无法消除被电子邮件轰炸的可能性，但您可以采取一些预防和保护措施来减少其影响。这里是其中的一些：
1] 使用防病毒软件和防火墙(1] Use anti-virus software and firewall)——您可以通过使用防病毒软件和设置防火墙来限制流量，从而减少被攻击的机会。
使用电子邮件过滤器应用程序(Use email filter applications)-电子邮件(Email)过滤器是用于通过根据源地址过滤电子邮件来管理未经请求的电子邮件的软件包。Mac OS常用的一些电子邮件过滤器是：
- 垃圾邮件扫描
- 垃圾邮件围栏
- POP文件
- 个人反垃圾邮件 X5
(Filter)适用于Windows的(Windows)过滤器包工具包括：
- 电子邮件选择器
- 垃圾邮件克星
- 仙人掌垃圾邮件过滤器
- 垃圾邮件杀手
2] 使用代理服务器(2] Use Proxy Servers)——很难对来自不同 IP 地址的每一个电子邮件炸弹进行垃圾邮件和过滤。这种情况可以在代理服务器的帮助下得到缓解。代理服务器是特定网络中的所有其他计算机都连接到的计算机。代理服务器有一些规则来过滤它收到的请求连接到它的计算机的信息和资源的消息。这有助于在将来自可疑 IP 地址的恶意请求和消息发送到代理服务器的客户端之前对其进行过滤。
3] 使用简单邮件传输协议 (SMTP) -(3] Using Simple Mail Transfer Protocol (SMTP)- )拒绝(Denial)服务(Service)攻击也可以使用SMTP来解决， SMTP是一种验证跨Internet协议的消息交换的方法。客户端使用邮局协议(Post Office Protocol)( POP ) 或Internet 消息访问协议(Internet Message Access Protocol)( IMAP )访问他们的邮箱。然后，邮件提交代理(Mail Submission Agent)通过SMTP将邮件或信息传输到邮件传输代理(Mail Transfer Agent)( MTA )。在连接到SMTP时，MTA分析发件人的邮件交换记录和IP地址，如果发现可疑则拒绝该邮件。在数据交换过程中会处理身份验证和协商等安全(Security)机制。
确定电子邮件炸弹的来源很重要，一旦确定，您需要配置路由器或防火墙并阻止来自该地址的传入数据包。
阅读下一篇：(Read next:) 屏蔽电子邮件地址的好处。
Email Bombing and Spamming, and ways to protect yourself
Email bombing is a form of internet abuse in which massive volumes of identical emails are sent to a specific email address to affect the operating system of a computer. When the mailbox gets flooded with countless unwanted emails, its capacity gets exhausted, leading to an inability to receive further emails. This may be done to prevent the victim from receiving or noticing some other important message in their mail. A sluggish system or inability to send or receive emails can be indications of getting email bombed. This happens because the system is already pre-occupied with processing countless emails.
Email Bombing and Spamming
There are three methods of email bombing: Mass mailing, List linking and ZIP bombing. Mass mailing involves sending several duplicate emails to the same address but can be easily detected by spam filters. The second, List linking, involves subscribing the target email address to different email list subscriptions. The user would always receive spam mail from all these subscriptions and will have to manually unsubscribe from each list separately. Email bombing done using ZIP archived attachments containing millions and billions of characters is known as ZIP bombing. Mail servers checking the mail with anti-virus software would require a greater amount of processing power, possibly resulting in Denial of Service.
While you cannot eliminate the chances of being email bombed, there are some preventive & protective measures you can take to reduce their effect. Here are some of them:
1] Use anti-virus software and firewall – You can reduce the chances of being attacked, by using anti-virus and putting up a firewall configured to restrict traffic.
Use email filter applications– Email filters are packages that are used to manage unsolicited emails by filtering emails according to the source address. Some of the email filters that are commonly used for Mac OS are:
- SpamSweep
- Spamfence
- POPFile
- Personal AntiSpam X5
Filter package tools for Windows include:
- Email Chomper
- Spam Buster
- Cactus Spam Filter
- SpamKiller
2] Use Proxy Servers– It is difficult to spam and filter each and every email bomb coming from different IP addresses. Such a situation could be mitigated with the help of proxy servers. A proxy server is a computer to which all other computers in a particular network are connected. The proxy server has certain rules for filtering the messages it receives requesting for information and resources of the computers connected to it. This helps in filtering malicious requests and messages from suspicious IP addresses before they are sent to the clients of the proxy server.
3] Using Simple Mail Transfer Protocol (SMTP)- Denial of Service attacks can also be solved using SMTP which is a method of authenticating the exchange of messages across Internet protocols. The clients access their mailbox using Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP). Through SMTP, the Mail Submission Agent then transfers a mail or information to the Mail Transfer Agent (MTA). On connecting to the SMTP, the MTA analyses the mail exchange record and IP address of the sender and reject the message if they are found suspicious. Security mechanisms such as authentication and negotiation are processed during the exchange of data.
It is important that you identify the source of the email bombs and once you have identified it, you need to configure your router or firewall and prevent incoming packets from that address.
Read next: Benefits of Masking Email Address.
