이 코드를 pre태그에 넣으면 오류발생
link=`expr “$ls” : ‘.*-> \(.*\)$’`
*** Error in `apache2': corrupted double-linked list: 0x0000565022316df0 *** [Tue Oct 24 06:49:56.116709 2017] [core:notice] [pid 1] AH00051: child pid 180 exit signal Aborted (6), possible coredump in /etc/apache2 *** Error in `apache2': double free or corruption (out): 0x000056502236b360 *** [Tue Oct 24 06:51:58.240351 2017] [core:notice] [pid 1] AH00051: child pid 201 exit signal Aborted (6), possible coredump in /etc/apache2 *** Error in `apache2': double free or corruption (out): 0x0000556db917a100 *** 172.19.0.2 - - [24/Oct/2017:15:06:17 +0000] "GET /favicon.ico HTTP/1.1" 200 191 "http://memo.polypia.net/archives/2739?preview_id=2739&preview_nonce=0920547848&post_format=standard&_thumbnail_id=-1&preview=true" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36" [Tue Oct 24 15:06:17.573774 2017] [core:notice] [pid 1] AH00051: child pid 239 exit signal Aborted (6), possible coredump in /etc/apache2 *** Error in `apache2': free(): invalid pointer: 0x00007fecef58b26e *** 172.19.0.2 - - [24/Oct/2017:15:06:24 +0000] "GET /favicon.ico HTTP/1.1" 200 191 "http://memo.polypia.net/archives/2739?preview_id=2739&preview_nonce=0920547848&post_format=standard&_thumbnail_id=-1&preview=true" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36" [Tue Oct 24 15:06:25.582744 2017] [core:notice] [pid 1] AH00051: child pid 240 exit signal Aborted (6), possible coredump in /etc/apache2
정확히 어느 부분이 오류포인트인지 정확히 모르겠는데 워드프레스에서 일부 코드가 escape되서 문자열을 실행코드로 인식하는게 아닌가 싶다.
퍼블릭 글쓰기 권한이 있는 워드프레스에서 해당코드를 활용하면 서버단의 php를 실행시키는 공격이 가능하지 않을까