CVE:CVE-2007-3377
CNNVD:CNNVD-200706-406
Net::DNS是用Perl实现的DNS解析器。 
Net::DNS实现上存在漏洞，远程攻击者可能利用此漏洞导致DNS服务器被欺骗或拒绝服务。
在Net::DNS中ID序列是在header.pm中确定的：
{
my $id = int rand(MAX_ID);
sub nextid {
return $id++ % (MAX_ID + 1); 
}
}
如果使用了这个模块的话就会设置$id，然后仅是简单的递增，这可能导致两个后果：
1) 序列号可预测，简化了DNS欺骗攻击；
2) 如果在fork服务器中使用Net::DNS的话，则通常会在父进程使用。除非父进程在接受请求之间进行DNS查询，否则每个子进程都会以相同的$id值开始并经历相同的id序列。由于源端口也可能是固定的，因此一个子进程很可能接受之前子进程所发送查询的回复。
solution:Upgrade nlnet_labs net_dns to a higher version than 0.14,0.20,0.21,0.22,0.23,0.24,0.25,0.26,0.27,0.28,0.29,0.30,0.31,0.32,0.33,0.34,0.34_02,0.34_03,0.35,0.36,0.37,0.38,0.38_01,0.38_02,0.39,0.39_01,0.39_02,0.40,0.40_01,0.41,0.42,0.42_01,0.42_02,0.43,0.44,0.44_01,0.44_02,0.45,0.45_01,0.46,0.47,0.47_01,0.48,0.48_01,0.48_02,0.48_03,0.49,0.49_01,0.49_02,0.49_03,0.50,0.51,0.51_01,0.51_02,0.52,0.53,0.53_01,0.53_02,0.54,0.55,0.56,0.57,0.58,0.59,and avoid the version 0.14,0.20,0.21,0.22,0.23,0.24,0.25,0.26,0.27,0.28,0.29,0.30,0.31,0.32,0.33,0.34,0.34_02,0.34_03,0.35,0.36,0.37,0.38,0.38_01,0.38_02,0.39,0.39_01,0.39_02,0.40,0.40_01,0.41,0.42,0.42_01,0.42_02,0.43,0.44,0.44_01,0.44_02,0.45,0.45_01,0.46,0.47,0.47_01,0.48,0.48_01,0.48_02,0.48_03,0.49,0.49_01,0.49_02,0.49_03,0.50,0.51,0.51_01,0.51_02,0.52,0.53,0.53_01,0.53_02,0.54,0.55,0.56,0.57,0.58,0.59