Bash爆出远程解析命令执行漏洞(CVE-2014-6271),波及各大Linux发行版与MacOSX系统。漏洞可以直接在Bash支持的Web CGI环境下远程执行任意命令。传送门 bash注入公开之后根据官方的文档发现,攻击者只要保持 $ env x='() { :;}; echo vulnerable' bash -c "echo this is a test" 中前四个字符不改变,也就是'(){ 固定,后面的:;}中符合规定的语法就可以进行攻击测试。虽然漏洞的影响非常大,但是相比于‘Openssl’来说,利用的环境是有限的。 防御bash注入的方法,首先需要更新bash,yum update下就OK了,更新到bash-4.1.2-15,或者是添加mod_security: [ Request Header values:
SecRule REQUEST_HEADERS "^\(\) {" "phase:1,deny,id:1000000,t:urlDecode,status:400,log,msg:'CVE-2014-6271 - Bash Attack'"
SERVER_PROTOCOL values:
SecRule REQUEST_LINE "\(\) {" "phase:1,deny,id:1000001,status:400,log,msg:'CVE-2014-6271 - Bash Attack'"
GET/POST names:
SecRule ARGS_NAMES "^\(\) {" "phase:2,deny,id:1000002,t:urlDecode,t:urlDecodeUni,status:400,log,msg:'CVE-2014-6271 - Bash Attack'"
GET/POST values:
SecRule ARGS "^\(\) {" "phase:2,deny,id:1000003,t:urlDecode,t:urlDecodeUni,status:400,log,msg:'CVE-2014-6271 - Bash Attack'"
File names for uploads:
SecRule FILES_NAMES "^\(\) {" "phase:2,deny,id:1000004,t:urlDecode,t:urlDecodeUni,status:400,log,msg:'CVE-2014-6271 - Bash Att ] 虽然有人给出了在iptable中添加规则,但是觉得在iptable中添加规则会规定的太死,不过也可以去尝试下 [ iptables --append INPUT -m string --algo kmp --hex-string '|28 29 20 7B|' --jump DROP
iptables using -m string --hex-string '|28 29 20 7B|' ]
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