7. Scanners

 

Enough research will tend to support your theory.

 Murphy's Law of Research

This is the platform dependent part of Scanners (i).

7.1. Finding targets

First a sample from file to show how the sed part is supposed to work.

And now the output of find_exec.sh for both the big and the small set of target executables. Typical Linux distributions have very few statically linked programs. On traditional system the number is much higher.

7.2. Scan entry point

See Sections for the illustrative description of a dumped ELF header.

Output: out/sparc-debian2.2-linux/scanner/entry_point/big.static
files=0002; detected=0000

Output: out/sparc-debian2.2-linux/scanner/entry_point/big.dynamic
files=0628; detected=0000

Well, on a clean system there are absolutely no deviations. Now we let the script oose on all infected executables produced from the sources of this document. Only a few are detected. Which means there is cure against this vulnerability (see The entry point). In the following output ep means "entry point" and sot is "start of .text".

Output: out/sparc-debian2.2-linux/scanner/entry_point/small.dynamic
segment_padding/e1i1/tcsh_infected           ep=0x57500    sot=0x11d9c   
segment_padding/e1i1/perl_infected           ep=0x9fcd0    sot=0x1eed0   
segment_padding/e1i1/mt_infected             ep=0x14390    sot=0x10d78   
segment_padding/e1i1/bash_infected           ep=0x85770    sot=0x1f598   
segment_padding/e1i1/strip_bash_infected     ep=0x85770    sot=0x1f598   
files=0005; detected=0005

7.3. Scan segments

Note that only the last few lines of output are shown.

On this installation at least 628 + 2 files are possible targets for Segment padding infection. So on to all infected executables created from the sources of this document. Again only the last few lines of output is shown. It's enough to see that all infected files are detected.

Output: out/sparc-debian2.2-linux/scanner/segment/small.dynamic
CHECK: 61441 > 65536; 0xf001 > 0x10000
CHECK: tmp/sparc-debian2.2-linux/segment_padding/e1i1/bash_infected
CHECK: src/scanner/segment/action.inc#17
CHECK: (delta) > (0x10000)
CHECK: 61445 > 65536; 0xf005 > 0x10000
CHECK: tmp/sparc-debian2.2-linux/segment_padding/e1i1/strip_bash_infected
CHECK: src/scanner/segment/action.inc#17
CHECK: (delta) > (0x10000)
CHECK: 61445 > 65536; 0xf005 > 0x10000
files=5; ok=5; det_page=0; det_align=5; min=0xf001; max=0xf005

7.4. Scan file size