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GreyNoise's findings raise important questions about the effectiveness of pre-advisory notifications in preventing Telnet breaches. Can we rely on such warnings to mitigate the impact of emerging vulnerabilities? The answer lies in a better understanding of the complex dynamics at play in this high-stakes game of cat and mouse between telcos, security experts, and threat intelligence firms.
The discovery of an ancient Telnet flaw has led to a global re-evaluation of the telco industry's security measures. A 65% drop in Telnet sessions occurred six days before a critical vulnerability was made public, suggesting possible pre-advisory notification by infrastructure operators. Port 23 filtering implemented by Tier 1 backbone providers may have mitigated the impact of the vulnerability. Cloud providers were largely unaffected due to their private peering arrangements, while residential and enterprise ISPs saw a significant decrease in Telnet sessions. The incident highlights the need for transparency and collaboration between industry leaders and security experts to address emerging threats.
The world of cybersecurity has witnessed numerous high-profile breaches and exploits, but a recent development has left experts abuzz with curiosity. The discovery of an ancient Telnet flaw, which allows for trivial root access exploitation, has led to a global re-evaluation of the telco industry's security measures. This article aims to delve into the intricacies of this case, exploring the events leading up to the public disclosure of CVE-2026-24061, and shedding light on the intriguing theories surrounding the pre-advisory notification that may have tipped off telcos about the impending vulnerability.
In January 2026, a critical Telnet vulnerability was made public, with security advisories going live six days later. However, analysis by threat intelligence firm GreyNoise suggests that global Telnet traffic plummeted on January 14, just six days before the advisory releases. The data indicates a 65% drop in Telnet sessions within an hour and an astonishing 83% decline within two hours, with daily sessions decreasing from 914,000 to approximately 373,000.
GreyNoise's findings imply that infrastructure operators may have received information about the make-me-root flaw before advisories went public. A backbone or transit provider - possibly responding to a coordinated request, possibly acting on their own assessment - implemented port 23 filtering on transit links. The filtering went live on January 14, followed by the public disclosure of the vulnerability on January 20.
The researchers behind GreyNoise note that correlation does not equal causation but argue that the combination of events - Tier 1 backbone implementing what appears to be port 23 filtering, followed by the disclosure of a trivially exploitable root-access Telnet vulnerability, and subsequently a CISA KEV listing four days later - warrants further consideration.
Cloud providers were largely unaffected by this sudden drop in Telnet sessions, with some, such as AWS, even experiencing an increase in traffic. The researchers attribute this discrepancy to cloud providers having extensive private peering at major IXPs that bypass traditional transit backbone paths. Residential and enterprise ISPs, on the other hand, saw a significant decrease in Telnet sessions, with US residential ISP Telnet traffic dropping within the US maintenance window hours.
The implications of this event are multifaceted. The possibility that one or more Tier 1 transit providers in North America implemented port 23 filtering prior to the public disclosure of the vulnerability raises questions about communication channels and pre-advisory notifications between telcos and security advisories.
While it is impossible to prove with certainty that there was a pre-advisory notification, the data and expert analysis suggest that this theory warrants investigation. The coordinated response by infrastructure operators and the subsequent public disclosure highlight the complex interplay between industry stakeholders and their efforts to address emerging vulnerabilities.
As the cybersecurity landscape continues to evolve, it becomes increasingly clear that the lines between proactive measures and post-hoc rationalization are often blurred. The Telnet Telco Takedown serves as a poignant reminder of the need for transparency and collaboration between industry leaders and security experts in the face of emerging threats.
In conclusion, the recent discovery of an ancient Telnet flaw has sparked a global discussion about the role of pre-advisory notifications in preventing security breaches. As experts delve deeper into this complex case, it is essential to prioritize open communication, cooperation, and proactive measures to safeguard against similar vulnerabilities in the future.
GreyNoise's findings raise important questions about the effectiveness of pre-advisory notifications in preventing Telnet breaches. Can we rely on such warnings to mitigate the impact of emerging vulnerabilities? The answer lies in a better understanding of the complex dynamics at play in this high-stakes game of cat and mouse between telcos, security experts, and threat intelligence firms.
Related Information:
https://www.ethicalhackingnews.com/articles/Unveiling-the-Telnet-Telco-Takedown-A-Global-Security-Conundrum-ehn.shtml
https://go.theregister.com/feed/www.theregister.com/2026/02/11/were_telcos_tipped_off_to/
https://www.theregister.com/2026/02/11/were_telcos_tipped_off_to/
https://www.newsbreak.com/news/4488845833379-were-telcos-tipped-off-to-that-ancient-telnet-bug-cyber-pros-say-the-signs-stack-up
Published: Wed Feb 18 01:07:29 2026 by llama3.2 3B Q4_K_M
