INTERNET STORM CENTER SPOTLIGHT
ISC provides a free analysis and warning service to thousands of Internet users and organizations, and is actively working with Internet Service Providers to fight back against the most malicious attackers. https://isc.sans.edu/about.html
New Variant of Crypto Confidence Scam
Published: 2025-05-21
Last Updated: 2025-05-21 15:26:09 UTC
by Johannes Ullrich (Version: 1)
In February, we had a few diaries about crypto wallet scams. We saw these scams use YouTube comments, but they happened via other platforms and messaging systems, not just YouTube. The scam was a bit convoluted: The scammer posted the secret key to their crypto wallet. Usually, this would put their crypto wallet at risk of being emptied. But the wallet they used came with a twist: A second key was required. The scammer counted on the victim paying the transaction fee, which the scammer would receive, before attempting to withdraw the funds.
This is a classic "confidence scheme" or "advance fee" scheme. The victim believes they are scamming the attacker out of their money. Instead, they are being robbed. These types of scams are amazingly successful in real life and online. They rely on greedy victims attempting to get something for free (or cheap).
I recently started seeing a new variation of this scam, this time mostly via X direct messages ...
Read the full entry: https://isc.sans.edu/diary/New+Variant+of+Crypto+Confidence+Scam/31968/
Researchers Scanning the Internet
Published: 2025-05-20
Last Updated: 2025-05-20 13:59:12 UTC
by Johannes Ullrich (Version: 1)
We have been using our data to identify researchers scanning the internet for a few years. Currently, we are tracking 36 groups performing such scans, and our data feed of the IP addresses used contains around 33k addresses.
Of course, no clear definition of when a scan is inappropriate exists. Some consider any scan performed nationally and without permission to be unethical. Others have a higher bar, for example, considering scans appropriate if they do not exploit vulnerabilities or cause damage. Legal frameworks vary around the world.
Earlier today, Caleb reminded me of RFC 9511, which I believe offers some good ideas and should be considered if you plan to perform an internet-wide scan. The RFC is entitled "Attribution of Internet Probes." It gets to one of the main issues: Identify yourself if you are performing these scans. This way, if you are causing problems, targets can contact you. This should be a minimum requirement to limit unintentional damage.
Can a simple "scan" cause damage? Of course, it can! We had plenty of examples of such scans causing problems. My favorite example is an old Cisco bug that caused routers to crash if they were scanned with empty UDP packets.
RFC9511 suggests adding a URL to your probe packets and a probe description file at "/.well-known/probing.txt." The IP address the probe originates from should reverse resolve to a hostname, and the probe description file can be found at that hostname. Alternatively, the host the probe originates from should run a web server offering the file. Or the probe description URL should be included as a payload.
For web-based scanning, I see many scanners adding a URL to the user-agent header, which I think fulfills what RFC 9511 is attempting to achieve ...
Read the full entry: https://isc.sans.edu/diary/Researchers+Scanning+the+Internet/31964/
Web Scanning SonicWall for CVE-2021-20016 - Update
Published: 2025-05-14
Last Updated: 2025-05-15 01:23:29 UTC
by Guy Bruneau (Version: 1)
I published on the 29 Apr 2025 a diary on scanning activity looking for SonicWall and since this publication this activity has grown 10-fold. Over the past 14 days, several BACS students have reported activity related to SonicWall scans all related for the same 2 URLs previously mentioned in my last diary. My own DShield sensor was probed by 25 separate IPs during those last 14 days. The three most active IPs were all from the same subnet ...
Read the full entry: https://isc.sans.edu/diary/Web+Scanning+SonicWall+for+CVE202120016+Update/31952/