I had a question on a job interview:

How can you execute (run) the program with the user user1 without sudo privileges and without access to the root account:

$ whoami
$ ls -l ~/binary_program
-rw-r--r-- 1 root root 126160 Jan 17 18:57 /home/user1/binary_program

2 Answers 2


You can use the Linux dynamic linker/loader directly to run ELF executables for which you have read, but not execute rights:

$ /lib/ld-linux.so.* /home/user1/binary_program

When an ELF executable is executed ordinarily, the dynamic linker which is stored in the .interp section of the program code is used. Reasons for invoking the dynamic linker directly (outside job interviews) include passing it command-line options to modify its behaviour.

Note that the actual location of the dynamic linker may very depending on the environment, for instance in 64-bit Ubuntu the linker is at /lib64/ld-linux-x86-64.so.2.


Since you have read permission:

$ cp ~/binary_program my_binary
$ chmod +x my_binary
$ ./my_binary

Of course this will not auto-magically grant you escalated privileges. You would still be executing that binary as a regular user.

  • 4
    @user2555595 I'm afraid you're wrong. Try removing the execute bit on a file you own and executing it. Even root gets "permission denied" when executing a file without the execute bit set.
    – Joseph R.
    Sep 28, 2014 at 7:18
  • you are right, thank you for the information Sep 28, 2014 at 7:24
  • 5
    @user2555595 That only applies for scripts, not binaries. More specifically only bash or POSIX shell scripts if bash is invoked as the interpreter. Sep 28, 2014 at 7:25
  • Thank you for your information, people! Have a nice day!
    – user63431
    Sep 28, 2014 at 8:41
  • 2
    @inivanoff1 Please don't forget to mark one of the answers "Accepted" so that people know this question is solved.
    – Joseph R.
    Sep 28, 2014 at 22:04

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