github splunk/security_content v5.27.0

6 hours ago

🚀 Key Highlights

  • 🚨 Linux Copy Fail Privilege Escalation (CVE-2026-31431): Added a new detection: Linux Auditd Copy Fail Privilege Escalation to identify exploitation of the Copy Fail vulnerability, a Linux kernel flaw that enables unprivileged users to perform controlled writes to file page cache and escalate privileges to root. This analytic leverages auditd telemetry to detect suspicious modification patterns targeting setuid binaries, providing early visibility into local privilege escalation attempts across affected Linux systems.

  • 🔐 Cisco Secure Access Analytics: Introduced a new analytic story for Cisco Secure Access, leveraging firewall telemetry to detect suspicious access patterns. This release includes updates to existing detections: Large ICMP Traffic, Outbound SMB Traffic, Outbound LDAP Traffic, and Windows RDP Network Brute Force Attempts enabling them to operate with Cisco Secure Access Firewall data, validated through simulated attack scenarios to improve visibility into adversary activity traversing modern cloud-delivered security controls.

  • 🪟 Windows Threat Detection Expansion: Significantly expanded coverage across multiple analytic stories with the addition of a broad set of new detections targeting modern Windows attack techniques, including PowerShell abuse, process injection, privilege escalation, registry manipulation, cloud and Azure activity, RMM tool usage, and C2 frameworks such as Cobalt Strike, Metasploit, and custom agents. These analytics enhance visibility into attacker behaviors like defense evasion (EDR bypass, obfuscation, EFI tampering), persistence (scheduled tasks, file association changes, GPO abuse), credential access (LAPS harvesting, keychain-like data access), and lateral movement and exfiltration, while also covering emerging tradecraft such as Cloudflared tunnels, Devtunnels, and supply chain tooling abuse—providing deeper detection across the Windows attack lifecycle.

  • ⌨️ VIP Keylogger (.NET Stealer) Detection Coverage: Introduced new analytics to strengthen detection of VIP Keylogger and related .NET-based infostealers by focusing on behavioral indicators of stealthy execution and persistence. New detections: PowerShell Environment Variable Execution, Windows Anomalous Registry Value Length in Environment Key, PowerShell PInvoke Process Injection API Chain, and Windows Proxy Execution of .NET Utilities via Scripts surface patterns such as encoded payload staging in registry keys, script-driven execution of trusted .NET binaries, and in-memory process injection techniques, improving visibility into credential theft operations, obfuscated execution chains, and defense evasion commonly used in modern phishing-delivered stealer campaigns.

New Analytic Story - [2]

New Analytics - [67]

Other Updates

  • Refined multiple detections using diverse telemetry sources to reduce false positives and enhance regex accuracy. (Pull Request)

  • Updated all detections to align with MITRE ATT&CK v19 technique IDs, ensuring consistency with the latest framework and improving mapping accuracy for threat coverage, reporting, and correlation.

Note: This is the final release for ESCU v5.x. Starting with ESCU v6.0, the STRT will use new internal tooling instead of contentctl to validate, package, and publish ESCU releases. For more information, see https://github.com/splunk/contentctl/blob/main/README.md

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