LookupError: unknown encoding: idna

[kastahl]

I get an exception when scanning some targets using targets file. When scanning these targets manually, it works fine.

I'm using the ssh-audit.exe in Version 2.5 on a Windows 10 VM.
For me it looks like to be an issue of missing import: import encodings.idna

An exception occurred while scanning 10.2xx.xx.xx:22:
Traceback (most recent call last):
File "ssh-audit.py", line 1017, in target_worker_thread
File "ssh-audit.py", line 842, in audit
File "ssh_socket.py", line 155, in connect
File "ssh_socket.py", line 85, in _resolve
File "socket.py", line 953, in getaddrinfo
LookupError: unknown encoding: idna

---

An exception occurred while scanning 10.2xx.xxx.xx:22:
Traceback (most recent call last):
File "ssh-audit.py", line 1017, in target_worker_thread
File "ssh-audit.py", line 842, in audit
File "ssh_socket.py", line 155, in connect
File "ssh_socket.py", line 85, in _resolve
File "socket.py", line 953, in getaddrinfo
LookupError: unknown encoding: idna

---

An exception occurred while scanning 10.2xx.xxx.xx:22:
Traceback (most recent call last):
File "ssh-audit.py", line 1017, in target_worker_thread
File "ssh-audit.py", line 842, in audit
File "ssh_socket.py", line 155, in connect
File "ssh_socket.py", line 85, in _resolve
File "socket.py", line 953, in getaddrinfo
LookupError: unknown encoding: idna

---

An exception occurred while scanning 10.2xx.xx.xx:22:
Traceback (most recent call last):
File "ssh-audit.py", line 1017, in target_worker_thread
File "ssh-audit.py", line 842, in audit
File "ssh_socket.py", line 155, in connect
File "ssh_socket.py", line 85, in _resolve
File "socket.py", line 953, in getaddrinfo
LookupError: unknown encoding: idna

---

An exception occurred while scanning 10.2xx.xxx.xx:22:
Traceback (most recent call last):
File "ssh-audit.py", line 1017, in target_worker_thread
File "ssh-audit.py", line 842, in audit
File "ssh_socket.py", line 155, in connect
File "ssh_socket.py", line 85, in _resolve
File "socket.py", line 953, in getaddrinfo
LookupError: unknown encoding: idna

[thecliguy]

@kastahl I have done some debugging and it looks like this problem is very specfic to the executable version of ssh-audit for Windows which is built using pyinstaller.

Please can you tell me, how many targets do you have in your targets file?

[kastahl]

@kastahl I have done some debugging and it looks like this problem is very specfic to the executable version of ssh-audit for Windows which is built using pyinstaller.

Please can you tell me, how many targets do you have in your targets file?

@thecliguy There are just 9 targets in the targets file. The first 4 targets will be processed.

[thecliguy]

@kastahl Are all 9 targets scanned successfully if you use the parameter --threads=1?

EG:

C:\temp\ssh-audit.exe --targets=hosts.txt --threads=1

[kastahl]

--threads=1

@thecliguy That works and all targets will be processed now. :)

[thecliguy]

@kastahl Thanks for testing, much appreciated.

This confirms my suspicion that the problem relates to multithreading and appears only to affect the Windows executable version of ssh-audit.

Please leave this ticket open because although we now have a workaround (which is to avoid multiple threads), there is still a bug that needs to be fixed properly.

[jtesta]

Thanks for helping with this, @thecliguy. I'll investigate this further next time I do testing on my Windows machine.

[jtesta]

Looks like this is related to the following CPython bug: python/cpython#73474

Someone in that thread suggested a workaround. I'll give that a try.

[jtesta]

@kastahl : I checked in a fix for this issue. A new release will be coming soon with it included!

I'll keep this issue open as a reminder to ping you once the release is complete.

[thecliguy]

@jtesta : I've just read #152... When the workaround is invoked, a warning is printed advising that: "...Multi-threaded scanning can be enabled by installing the idna module (pip install idna)".

This problem is only known to occur with the executable version of ssh-audit for Windows which is built using pyinstaller...

My understanding is that all dependencies including the Python interpreter are bundled within the Windows executable. Therefore, a Windows user doesn't need Python to be installed. So on that basis, I don't think the advice of installing the idna module is applicable or actionable when dealing with the Windows executable because it doesn't interact with a locally installed copy of Python.

[jtesta]

@thecliguy: I thought the problem happened in both the packaged executable as well as with the unpackaged source files. But when I went back and tried to reproduce both cases, I could no longer trigger the crash. I've since upgraded my build machine from Python v3.9 to v3.11, and I suspect that this addressed the root cause (!). Hence, I've commented out the workaround that I applied to the source tree.

If anyone notices this same crash using the latest commit in master, please chime in!

[oam7575]

I have just carried out some basic testing with a variety of different python versions. Details below

Windows 10 22H2
ssh-audit master
command : "python.exe h:\GIT\ssh-audit\ssh-audit.py -T h:\GIT\ssh-audit\test.txt --threads=4"
text file contains 2x hosts with 2x formats for each host.
1x will succeed and 1x will fail for each ( deliberate incorrect port number )

• Python 3.6.2 - Appears OK - No Errors
• Python 3.7.0 - Appears OK - No Errors
• Python 3.8.0 - Appears OK - No Errors
• Python 3.9.13 - Appears OK - No Errors
• Python 3.10.11 - Appears OK - No Errors
• Python 3.11.3 - Appears OK - No Errors

[jtesta]

@oam7575 : thanks for doing all this testing! Does the precompiled Windows executable have any trouble on your system?

[jtesta]

@kastahl : I think this issue is fixed in the Windows executable released in v2.9.0. If you're able to test it on your system, that would be a big help! Thanks!

[kastahl]

@jtesta I will try to test it in the next days. Will give feedback asap.

[jtesta]

@kastahl: Well, I suppose I'll close this issue, since v2.9.0 has been out for nearly 4 months, and no one has reported any problems with it. If you do run into the problem again, though, please re-open this issue.

Thanks for reporting it!