Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
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Detection of EtherRAT's SSH backdoor module that appends attacker-controlled public keys to authorized_keys. The rule correlates the creation of the .ssh directory with key injection and permission setting. It also identifies direct writes or appends to authorized_keys, and specific chmod operations on authorized_keys. Additionally, it looks for Node.js processes writing or appending to authorized_keys, indicating potential automated key injection.
The following analytic detects the creation of SSH key files in the ~/.ssh/ directory. It leverages filesystem data to identify new files in this specific path. This activity is significant because threat actors often create SSH keys to gain persistent access and escalate privileges on a compromised host. If confirmed malicious, this could allow attackers to remotely access the machine using the OpenSSH daemon service, leading to potential unauthorized control and data exfiltration.
The following analytic detects the modification of SSH Authorized Keys on Linux systems. It leverages process execution data from Endpoint Detection and Response (EDR) agents, specifically monitoring commands like "bash" and "cat" interacting with "authorized_keys" files. This activity is significant as adversaries often modify SSH Authorized Keys to establish persistent access to compromised endpoints. If confirmed malicious, this behavior could allow attackers to maintain unauthorized access, bypassing traditional authentication mechanisms and potentially leading to further exploitation or data exfiltration.
This KQL query analyzes Microsoft Entra ID (formerly Azure AD) sign-in and audit logs to identify potentially risky multi-factor authentication (MFA) registration events. It works by checking for MFA registrations initiated from a new, previously unseen IP address.
The query joins historical sign-in data with recent MFA-related events. It calculates how many unique days an IP address has been used by a specific user over the last 30 days. It then flags any MFA registration event from the last 24 hours where the IP address is a new IP (seen zero days before). The final results are filtered to exclude events from new user accounts (created in the last 60 days) to focus on more established accounts.
The query joins historical sign-in data with recent MFA-related events. It calculates how many unique days an IP address has been used by a specific user over the last 30 days. It then flags any MFA registration event from the last 24 hours where the IP address is a new IP (seen zero days before). The final results are filtered to exclude events from new user accounts (created in the last 60 days) to focus on more established accounts.
KQL Query from file: CVE-2024-7971 Patch Prioritization
Author: alex verboon @alexverboon.
Blogpost: https://www.verboon.info/2020/09/hunting-for-local-group-membership-changes.
Blogpost: https://www.verboon.info/2020/09/hunting-for-local-group-membership-changes.
Credentials were added to an application by UserA, after the application was granted admin consent rights by UserB
The Nobelium activity group has been observed adding credentials (x509 keys or password credentials) for one or more legitimate OAuth Applications or Service Principals, usually with existing Mail.Read or Mail.ReadWrite permissions, which grants the ability to read mail content from Exchange Online via Microsoft Graph or Outlook REST. Examples include mail archiving applications.
See Customer Guidance on Recent Nation-State Cyber Attacks for more on the Nobelium campaign (formerly known as Solorigate).
See Grant tenant-wide admin consent to an application for how to add admin consent to an application.
More Nobelium-related queries can be found listed under the See also section of this document.
References:
https://msrc-blog.microsoft.com/2020/12/13/customer-guidance-on-recent-nation-state-cyber-attacks/
https://docs.microsoft.com/azure/active-directory/manage-apps/grant-admin-consent
The Nobelium activity group has been observed adding credentials (x509 keys or password credentials) for one or more legitimate OAuth Applications or Service Principals, usually with existing Mail.Read or Mail.ReadWrite permissions, which grants the ability to read mail content from Exchange Online via Microsoft Graph or Outlook REST. Examples include mail archiving applications.
See Customer Guidance on Recent Nation-State Cyber Attacks for more on the Nobelium campaign (formerly known as Solorigate).
See Grant tenant-wide admin consent to an application for how to add admin consent to an application.
More Nobelium-related queries can be found listed under the See also section of this document.
References:
https://msrc-blog.microsoft.com/2020/12/13/customer-guidance-on-recent-nation-state-cyber-attacks/
https://docs.microsoft.com/azure/active-directory/manage-apps/grant-admin-consent
Intent:
- Use MTP capability to look for insider threat potential risk indicators
- Indicators would then serve as the building block for insider threat risk modeling in subsequent tools
Definition of Insider Threat:
"The potential for an individual who has or had authorized access to an organization's assets to use their access, either maliciously or unintentionally, to act in a way that could negatively affect the organization."
This collection of queries describes the different indicators that could be used to model and look for patterns suggesting an increased risk of an individual becoming a potential insider threat.
Note: no single indicator should be used as a lone determinant of insider threat activity, but should be part of an overall program to understand the increased risk to your organization's critical assets. This in turn is used to feed an investigation by a formal insider threat program to look at the context associated with the whole person to understand the implication of a set of indicators.
- Use MTP capability to look for insider threat potential risk indicators
- Indicators would then serve as the building block for insider threat risk modeling in subsequent tools
Definition of Insider Threat:
"The potential for an individual who has or had authorized access to an organization's assets to use their access, either maliciously or unintentionally, to act in a way that could negatively affect the organization."
This collection of queries describes the different indicators that could be used to model and look for patterns suggesting an increased risk of an individual becoming a potential insider threat.
Note: no single indicator should be used as a lone determinant of insider threat activity, but should be part of an overall program to understand the increased risk to your organization's critical assets. This in turn is used to feed an investigation by a formal insider threat program to look at the context associated with the whole person to understand the implication of a set of indicators.
Intent:
- Use MTP capability to look for insider threat potential risk indicators
- Indicators would then serve as the building block for insider threat risk modeling in subsequent tools
Definition of Insider Threat:
"The potential for an individual who has or had authorized access to an organization's assets to use their access, either maliciously or unintentionally, to act in a way that could negatively affect the organization."
This collection of queries describes the different indicators that could be used to model and look for patterns suggesting an increased risk of an individual becoming a potential insider threat.
Note: no single indicator should be used as a lone determinant of insider threat activity, but should be part of an overall program to understand the increased risk to your organization's critical assets. This in turn is used to feed an investigation by a formal insider threat program to look at the context associated with the whole person to understand the implication of a set of indicators.
- Use MTP capability to look for insider threat potential risk indicators
- Indicators would then serve as the building block for insider threat risk modeling in subsequent tools
Definition of Insider Threat:
"The potential for an individual who has or had authorized access to an organization's assets to use their access, either maliciously or unintentionally, to act in a way that could negatively affect the organization."
This collection of queries describes the different indicators that could be used to model and look for patterns suggesting an increased risk of an individual becoming a potential insider threat.
Note: no single indicator should be used as a lone determinant of insider threat activity, but should be part of an overall program to understand the increased risk to your organization's critical assets. This in turn is used to feed an investigation by a formal insider threat program to look at the context associated with the whole person to understand the implication of a set of indicators.
The analytic detects suspicious access or modification of the sshd_config file on Linux systems. It leverages data from Linux Auditd, focusing on command-line executions involving processes like "cat," "nano," "vim," and "vi" accessing the sshd_config file. This activity is significant because unauthorized changes to sshd_config can allow threat actors to redirect port connections or use unauthorized keys, potentially compromising the system. If confirmed malicious, this could lead to unauthorized access, privilege escalation, or persistent backdoor access, posing a severe security risk.
The analytic detects suspicious access or modification of the sshd_config file on Linux systems. It focuses on command-line executions involving processes like "cat," "nano," "vim," and "vi" accessing the sshd_config file. Unauthorized changes to sshd_config can allow threat actors to redirect port connections or use unauthorized keys, potentially compromising the system, leading to unauthorized access, privilege escalation, or persistent backdoor access.
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