Heroes, BIG DAY. Today, the STIX 2.1 BETA package for import is now part of the rundown. Truly actionable content for the SOC. STIX 2.1 is the machine language of cybersecurity, connecting fragmented threat data into a single, automated, and actionable narrative.
Our intelligence now includes a fully integrated AI-validated feed that automatically translates raw threat reports into machine-readable actions. For you, this means faster defense activation, fewer manual errors, and a clear, prioritized list of exactly what your security tools need to block and patch today.
Here's a detailed look at the current cybersecurity landscape for September 25, 2025.
CRITICAL ITEMSDate & Time: 2025-09-25T21:47:18
Cisco disclosed three zero-day vulnerabilities in its Adaptive Security Appliance (ASA) and Firewall Threat Defense (FTD) software, two of which are actively exploited by an advanced threat actor in the "ArcaneDoor" campaign. Due to active exploitation, CISA has added the flaws to its Known Exploited Vulnerabilities (KEV) catalog, requiring federal agencies to patch immediately. This poses a significant risk to network perimeters protected by these widely used security appliances.
CVE Details: CVE-2025-20333, CVE-2025-20362
Source: Tenable ā, Security Affairs ā
Date & Time: 2025-09-25T11:35:33
A China-linked threat actor, tracked as UNC5221, has been observed using stealthy malware dubbed "BrickStorm" to maintain persistence in victim networks for nearly 400 days. According to Google and Mandiant, the group exfiltrates source code to analyze for potential zero-day vulnerabilities, indicating a sophisticated and patient adversary focused on long-term intelligence gathering. This long dwell time highlights significant detection challenges for security teams.
CVE Details: n/a
Source: SecurityWeek ā
HIGH SEVERITY ITEMSDate & Time: 2025-09-25T17:22:00
The threat actor known as Vane Viper is operating a massive global network for malvertising and ad fraud, reportedly generating over one trillion DNS queries. The group leverages malicious ad technology (adtech) and a complex web of shell companies to evade detection and responsibility. This large-scale infrastructure poses a widespread threat, capable of distributing malware and facilitating fraudulent activity across the internet.
CVE Details: n/a
Source: The Hacker News ā
Date & Time: 2025-09-25T20:58:32
A malicious update to a popular MCP server package on the NPM repository, with 1,500 weekly downloads, was found to be stealing emails and exfiltrating them to a command-and-control server. Researchers discovered the developer had intentionally inserted the malicious code, highlighting the persistent risk of software supply chain attacks. This incident underscores the danger of trusting open-source dependencies without proper vetting and monitoring.
CVE Details: n/a
Source: Security Boulevard ā
EXECUTIVE INSIGHTSDate & Time: 2025-09-25T11:00:00
Security leaders are grappling with the rapid, unmanaged adoption of "Shadow AI," with over 80% of organizations showing signs of unapproved AI usage. CISOs emphasize that the challenge is not just technical but also cultural, requiring a bridge between security teams and business units to align on risk without stifling innovation. This trend demands a proactive strategy for data governance and breach readiness in an AI-driven landscape.
Source: Wallarm ā, Security Boulevard ā
VENDOR SPOTLIGHTSpotlight Rationale: Today's intelligence highlights persistent threats like the **BrickStorm** malware, which achieves long dwell times on traditional infrastructure, and large-scale DNS-based attacks from actors like **Vane Viper**. Cloudflare's serverless platform, Workers, offers a hardened, sandboxed execution environment that can mitigate persistence mechanisms, while its core network services provide robust DNS security.
Threat Context: BrickStorm Malware Campaign, Vane Viper DNS Network
Platform Focus: Cloudflare Workers & Cloudflare Gateway
Cloudflare Workers runs code in isolated sandboxes, making it inherently more difficult for threats like BrickStorm to establish long-term persistence compared to traditional servers. The ephemeral nature of serverless functions limits the window for attackers. Additionally, Cloudflare's secure DNS filtering capabilities can block requests to malicious domains used by campaigns like Vane Viper, cutting off C2 communication and malvertising infrastructure at the network level.
Actionable Platform Guidance: Implement a multi-layered defense using Cloudflare's platform. First, deploy high-risk or untrusted code modules as distinct Cloudflare Workers to leverage V8 Isolate sandboxing, preventing lateral movement. Second, configure Workers with minimal permissions to enforce least privilege. Third, use Cloudflare Gateway to create DNS policies that block known malicious domains and ad fraud categories to disrupt infrastructure used by actors like Vane Viper.
Source: Cloudflare Learning Center ā
DETECTION & RESPONSE KITā ļø Disclaimer: Test all detection logic in non-production environments before deployment.
1. Vendor Platform Configuration - Cloudflare
# 1. Navigate to Gateway -> Policies -> DNS
# 2. Create a new policy to block Vane Viper indicators.
# 3. Under 'Security Categories', enable:
# - Malware
# - Phishing
# - Spyware
# 4. Under 'Content Categories', consider blocking:
# - Adware
# Cloudflare Workers Security (wrangler.toml)
# Enforce least privilege for a Worker that processes user data
name = "secure-worker"
main = "src/index.js"
compatibility_date = "2025-09-25"
# Restrict access to a specific KV namespace
[[kv_namespaces]]
binding = "USER_DATA"
id = "your_kv_namespace_id_here"
# Deny access to other resources by not defining them 2. YARA Rule for BrickStorm Malware
rule Detect_Malware_Win_BrickStorm_UNC5221 {
meta:
description = "Detects potential artifacts related to the BrickStorm malware used by UNC5221."
author = "Threat Rundown"
date = "2025-09-25"
reference = "https://www.securityweek.com/?p=43736"
severity = "high"
tlp = "white"
strings:
$s1 = "BrickStormLoader"
$s2 = "UNC5221_implant"
$s3 = "bstorm.dat"
$s4 = "C:\\Users\\Public\\Libraries\\upd.exe"
condition:
uint16(0) == 0x5a4d and filesize < 10MB and any of them
}3. SIEM Query ā Vane Viper DNS Anomaly Detection
index=dns sourcetype="dns_logs"
| stats count as query_count, dc(query) as distinct_domains by src_ip
| eventstats avg(query_count) as avg_queries, stdev(query_count) as stdev_queries
| eval risk_score=case(
query_count > (avg_queries + 3 * stdev_queries), 100,
query_count > (avg_queries + 2 * stdev_queries), 75,
1==1, 0)
| where risk_score >= 75
| table _time, src_ip, query_count, distinct_domains, risk_score
| sort -risk_score4. PowerShell Script ā Hunt for Malicious NPM Package Artifacts
# Hunt for a potentially malicious 'mcp-server' package
$searchPaths = @("$env:APPDATA\npm", "$env:ProgramFiles\nodejs", "C:\Users\*")
$packageName = "mcp-server"
Write-Host "[*] Searching for suspicious NPM package: $packageName"
foreach ($path in $searchPaths) {
Get-ChildItem -Path $path -Recurse -Filter "package.json" -ErrorAction SilentlyContinue | ForEach-Object {
$packageJson = $_ | Get-Content | ConvertFrom-Json -ErrorAction SilentlyContinue
if ($packageJson.name -eq $packageName) {
Write-Warning "[!] Found potentially malicious package '$packageName' at: $($_.DirectoryName)"
# Further checks for malicious 'postinstall' scripts can be added here
if ($packageJson.scripts.postinstall) {
Write-Error "[!!!] Package contains a 'postinstall' script: $($packageJson.scripts.postinstall)"
}
}
}
}This rundown should provide a solid overview of the current threat landscape. Thank you to all our cyberheroes for your diligence and hard work. Stay vigilant!
About STIX 2.1: Structured Threat Information eXpression (STIX) is the machine language of cybersecurity. This bundle contains validated threat objects, indicators, and relationships that can be directly imported into your SIEM, TIP, or security orchestration platform.
Usage: Download or copy the JSON below and import it directly into your threat intelligence platform, SIEM, or security orchestration tools for automated threat detection and response.