Metasploit-framework: during msfvenom, "running msfupdate" suggestion should be send to stderr and not stdout

[funoverip]

The following message is printed to stdout instead of stderr, _silently_ breaking out the raw version of the shellcode, when the output of msfvenom is piped to additional commands , or redirected to a file.

"This copy of metasploit-framework is more than two weeks old.
Consider running 'msfupdate' to update to the latest version."

Steps to reproduce

root@linux:~# msfvenom -p <payload> -f raw <options> | my_selfmade_encoder.sh

or

root@linux:~# msfvenom -p <payload> -f raw <options> > /tmp/payload.raw
The raw shellcode is affected by this suggested message (and I have personally wasted 2 hours trying to figure out why my payload wasn't working any more :D )

root@linux:~# hexdump -C /tmp/payload.raw
00000000  54 68 69 73 20 63 6f 70  79 20 6f 66 20 6d 65 74  |This copy of met|
00000010  61 73 70 6c 6f 69 74 2d  66 72 61 6d 65 77 6f 72  |asploit-framewor|
00000020  6b 20 69 73 20 6d 6f 72  65 20 74 68 61 6e 20 74  |k is more than t|
00000030  77 6f 20 77 65 65 6b 73  20 6f 6c 64 2e 0a 20 43  |wo weeks old.. C|
00000040  6f 6e 73 69 64 65 72 20  72 75 6e 6e 69 6e 67 20  |onsider running |
00000050  27 6d 73 66 75 70 64 61  74 65 27 20 74 6f 20 75  |'msfupdate' to u|
00000060  70 64 61 74 65 20 74 6f  20 74 68 65 20 6c 61 74  |pdate to the lat|
00000070  65 73 74 20 76 65 72 73  69 6f 6e 2e 0a 48 31 c9  |est version..H1.|
00000080  48 81 e9 b1 ff ff ff 48  8d 05 ef ff ff ff 48 bb  |H......H......H.|
00000090  21 9a f0 09 d9 59 b5 dc  48 31 58 27 48 2d f8 ff  |!....Y..H1X'H-..|
000000a0  ff ff e2 f4 dd d2 73 ed  29 b1 79 dc 21 9a b1 58  |......s.).y.!..X|
000000b0  98 09 e7 8d 77 d2 c1 db  bc 11 3e 8e 41 d2 7b 5b  |....w.....>.A.{[|
000000c0  c1 11 3e 8e 01 d2 7b 7b  89 11 ba 6b 6b d0 bd 38  |..>...{{...kk..8|
000000d0  10 11 84 1c 8d a6 91 75  db 75 95 9d e0 53 fd 48  |.......u.u...S.H|
000000e0  d8 98 57 31 73 db a1 41  52 0b 95 57 63 a6 b8 08  |..W1s..AR..Wc...|

Expected behavior

The following message should be sent to stderr

"This copy of metasploit-framework is more than two weeks old.
Consider running 'msfupdate' to update to the latest version."

Current behavior

The following message is currently sent to stdout

"This copy of metasploit-framework is more than two weeks old.
Consider running 'msfupdate' to update to the latest version."

System stuff

Metasploit version

metasploit-framework 4.13.10-0kali1 amd64

I installed Metasploit with:

• [X ] Kali package via apt
• [ ] Omnibus installer (nightly)
• [ ] Commercial/Community installer (from http://www.rapid7.com/products/metasploit/download.jsp)
• [ ] Source install (please specify ruby version)

OS

Kali linux

[wvu-r7]

Oh, yuck.

[wvu-r7]

My gut instinct was to check our Omnibus package. Looks like a problem with msfwrapper.erb. cc @bcook-r7

[busterb]

well sure, that's the point. However we fix this, you will still have to 'Consider running 'msfupdate' to update to the latest version."'

[busterb]

See https://github.com/rapid7/metasploit-omnibus/pull/14/files for instance to find those wrapper script templates.

[wvu-r7]

@funoverip: Consider using msfvenom -o for now.

[busterb]

Fix above ^

[funoverip]

Awesome ! (Well, I did upgrade in the meantime but... )

[busterb]

Thanks, sorry for the surprising behavior and ensuing goose chase!