The Cybersecurity and Infrastructure Security Agency (CISA)'s Cyber Safety Review Board (CSRB) was established in May 2021 and is charged with reviewing major cybersecurity incidents and issuing guidance and recommendations where necessary. GreyNoise is cited as a primary source of ground truth in the CSRB's first report (direct PDF), published on July 11, 2022, covering the December 2021 Log4j event. GreyNoise employees testified to the Cyber Safety Review Board on our early observations of Log4j. In this post, we'll examine key takeaways from the report with a GreyNoise lens and discuss what present-day Log4j malicious activity may portend.
It may seem as if it's been a few years since the Log4j event ruined vacations and caused quite a stir across the internet. In reality, it's been just a little over six months since we published our "Log4j Analysis - What To Do Before The Next Big One" review of this mega-incident. Since that time, we've worked with the CSRB and provided our analyses and summaries of pertinent telemetry to help them craft their findings.
The most perspicacious paragraph in the CSRB's report may be this one:
Most importantly, however, the Log4j event is not over. The Board assesses that Log4j is an “endemic vulnerability” and that vulnerable instances of Log4j will remain in systems for many years to come, perhaps a decade or longer. Significant risk remains.
In fact, it reinforces their primary recommendation: "Organizations should be prepared to address Log4j vulnerabilities for years to come and continue to report (and escalate) observations of Log4j exploitation." (CSRB Log4j Report, pg. 6)
The CSRB further recommends (CSRB Log4j Report, pg. 7) that organizations:
This is all sound advice, but if your organization is starting from ground zero in any of those bullets, getting to a maturity level where they will each be effective will take time. Meanwhile, we've published three blogs on emerging, active exploit campaigns since the Log4j event:
Furthermore, CISA has added over 460 new Known Exploited Vulnerabilities (KEV) to their ever-growing catalog. That's quite a jump in the known attack surface, especially if you're still struggling to know if you have any of the entries in the KEV catalog in your environment.
While you're working on honing your internal asset, vulnerability, and software inventory telemetry, you can improve your ability to defend from emerging attacks by keeping an eye on attacker activity (something our tools and APIs are superb at), and ensuring your incident responders and analysts identify, block, or contain exploit attempts as quickly as possible. That's one area the CSRB took a light touch on in their report, but that we think is a crucial component of your safety and resilience practices.
Log4j is (sadly, unsurprisingly) alive and well:
This hourly view over the past two months shows regular, and often large amounts of activity by a handful (~50) of internet sources. In essence, Log4j has definitely become one of the many permanent and persistent components of internet "noise," and this is a further confirmation of CISA's posit that Log4j is here for the long haul. As if on queue, news broke of Iranian state-sponsored attackers using the Log4j exploit in very recent campaigns, just as we were preparing this post for publication.
If we take a look at what other activity is present from those source nodes, we make an interesting discovery:
While most of the nodes are only targeting the Log4j vulnerability, some are involved in SSH exploitation, hunting for nodes to add to the ever-expanding Mirai botnet clusters, or focusing on a more recent Atlassian vulnerability from this year.
However, one node has merely added Log4j to the inventory of exploits it has been using. It's not necessary to see all the tag names here, but you can explore these IPs in-depth at your convenience.
Building on the conclusion of the previous section, you can safely block all IPs associated with the Apache Log4j RCE Exploit Attempt tag or other emerging tags to give you and your operations teams breathing room to patch.
You are always welcome to use the GreyNoise product to help you separate internet noise from threats as an unauthenticated user on our site. For additional functionality and IP search capacity, create your own GreyNoise Community (free) account today.