‘Underminr’ Vulnerability Lets Attackers Hide Malicious Connections Behind Trusted Domains

Threat actors can abuse Underminr to hide connections to command-and-control (C&C) servers, as well as VPN and proxy connections, and to circumvent network egress policies.“In the simple form, the detection gap appears when DNS decisions, edge IPs, SNI, Host headers, and CDN tenant routing are not correlated. The endpoint sees an allowed DNS lookup while the connection can complete against a different hosted name,” ADAMnetworks says.According to the company, the attack technique has been abused in attacks to connect to domains hosted on CDN infrastructure shared with allowed domains, mostly via TCP connections on port 443, in which SNI exposes the intended TLS hostname.The Underminr vulnerability can be exploited using four different strategies to circumvent the DNS query monitoring and filtering service Protective DNS (PDNS).In real-world scenarios, attackers can launch attacks using malicious applications and shell scripts. The vulnerability can also be abused in ClickFix attacks, ADAMnetworks says.There are approximately 88 million domains potentially affected by Underminr, with internet infrastructure in the US, the UK, and Canada most impacted. Threat actors’ increased reliance on AI is expected to lead to a surge in attacks.“Once Underminr becomes parametric information for AI-generated malware, we could expect to see it in every attack that needs to evade protective DNS as part of the attack chain,” ADAMnetworks CEO David Redekop says.Related:$10 Domain Could Have Handed Hackers 25k Endpoints, Including in OT and Gov NetworksRelated:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

“In the simple form, the detection gap appears when DNS decisions, edge IPs, SNI, Host headers, and CDN tenant routing are not correlated. The endpoint sees an allowed DNS lookup while the connection can complete against a different hosted name,” ADAMnetworks says.According to the company, the attack technique has been abused in attacks to connect to domains hosted on CDN infrastructure shared with allowed domains, mostly via TCP connections on port 443, in which SNI exposes the intended TLS hostname.The Underminr vulnerability can be exploited using four different strategies to circumvent the DNS query monitoring and filtering service Protective DNS (PDNS).In real-world scenarios, attackers can launch attacks using malicious applications and shell scripts. The vulnerability can also be abused in ClickFix attacks, ADAMnetworks says.There are approximately 88 million domains potentially affected by Underminr, with internet infrastructure in the US, the UK, and Canada most impacted. Threat actors’ increased reliance on AI is expected to lead to a surge in attacks.“Once Underminr becomes parametric information for AI-generated malware, we could expect to see it in every attack that needs to evade protective DNS as part of the attack chain,” ADAMnetworks CEO David Redekop says.Related:$10 Domain Could Have Handed Hackers 25k Endpoints, Including in OT and Gov NetworksRelated:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

According to the company, the attack technique has been abused in attacks to connect to domains hosted on CDN infrastructure shared with allowed domains, mostly via TCP connections on port 443, in which SNI exposes the intended TLS hostname.The Underminr vulnerability can be exploited using four different strategies to circumvent the DNS query monitoring and filtering service Protective DNS (PDNS).In real-world scenarios, attackers can launch attacks using malicious applications and shell scripts. The vulnerability can also be abused in ClickFix attacks, ADAMnetworks says.There are approximately 88 million domains potentially affected by Underminr, with internet infrastructure in the US, the UK, and Canada most impacted. Threat actors’ increased reliance on AI is expected to lead to a surge in attacks.“Once Underminr becomes parametric information for AI-generated malware, we could expect to see it in every attack that needs to evade protective DNS as part of the attack chain,” ADAMnetworks CEO David Redekop says.Related:$10 Domain Could Have Handed Hackers 25k Endpoints, Including in OT and Gov NetworksRelated:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

The Underminr vulnerability can be exploited using four different strategies to circumvent the DNS query monitoring and filtering service Protective DNS (PDNS).In real-world scenarios, attackers can launch attacks using malicious applications and shell scripts. The vulnerability can also be abused in ClickFix attacks, ADAMnetworks says.There are approximately 88 million domains potentially affected by Underminr, with internet infrastructure in the US, the UK, and Canada most impacted. Threat actors’ increased reliance on AI is expected to lead to a surge in attacks.“Once Underminr becomes parametric information for AI-generated malware, we could expect to see it in every attack that needs to evade protective DNS as part of the attack chain,” ADAMnetworks CEO David Redekop says.Related:$10 Domain Could Have Handed Hackers 25k Endpoints, Including in OT and Gov NetworksRelated:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

In real-world scenarios, attackers can launch attacks using malicious applications and shell scripts. The vulnerability can also be abused in ClickFix attacks, ADAMnetworks says.There are approximately 88 million domains potentially affected by Underminr, with internet infrastructure in the US, the UK, and Canada most impacted. Threat actors’ increased reliance on AI is expected to lead to a surge in attacks.“Once Underminr becomes parametric information for AI-generated malware, we could expect to see it in every attack that needs to evade protective DNS as part of the attack chain,” ADAMnetworks CEO David Redekop says.Related:$10 Domain Could Have Handed Hackers 25k Endpoints, Including in OT and Gov NetworksRelated:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

There are approximately 88 million domains potentially affected by Underminr, with internet infrastructure in the US, the UK, and Canada most impacted. Threat actors’ increased reliance on AI is expected to lead to a surge in attacks.“Once Underminr becomes parametric information for AI-generated malware, we could expect to see it in every attack that needs to evade protective DNS as part of the attack chain,” ADAMnetworks CEO David Redekop says.Related:$10 Domain Could Have Handed Hackers 25k Endpoints, Including in OT and Gov NetworksRelated:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

“Once Underminr becomes parametric information for AI-generated malware, we could expect to see it in every attack that needs to evade protective DNS as part of the attack chain,” ADAMnetworks CEO David Redekop says.Related:$10 Domain Could Have Handed Hackers 25k Endpoints, Including in OT and Gov NetworksRelated:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

Related:$10 Domain Could Have Handed Hackers 25k Endpoints, Including in OT and Gov NetworksRelated:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

Related:US Disrupts Russian Espionage Operation Involving Hacked Routers and DNS HijackingRelated:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

Related:Complex Routing, Misconfigurations Exploited for Domain Spoofing in Phishing AttacksRelated:Microsoft Warns of ClickFix Attack Abusing DNS Lookups

Source: SecurityWeek