Hunting off the Red Banner

A Hunt for "Static Tundra"

Exposing a Nation-State Actor's Espionage on Unpatched Networks


The threat actor known as Static Tundra represents a significant and persistent risk, not through quick smash-and-grab operations, but through a long-term, calculated campaign of espionage. This Russian state-sponsored group is characterized by its patience and a methodical approach to compromising unpatched, end-of-life network devices. Their motivation is not immediate financial gain, but rather the strategic collection of sensitive intelligence over an extended period. The business impact of a Static Tundra compromise is substantial; it can lead to the exfiltration of confidential data, loss of intellectual property, and erosion of customer trust, with potentially catastrophic financial and reputational consequences.


Inaction against this threat is akin to leaving the front door unlocked and hoping no one notices. The adversary is actively scanning the internet for vulnerable systems, and once a foothold is established, they are notoriously difficult to dislodge. The financial repercussions can be immense, not only from data loss but also from the cost of extensive incident response, regulatory fines, and business interruption. Just as a small, unmaintained crack in a building's foundation can lead to a complete structural collapse over time, a single unpatched device can be the entry point for a long-term espionage campaign that undermines the entire security posture of an organization.

Given the potential for a long-term, silent compromise, the question we must collectively ask is, “What should we do as a team about this threat?”. It is paramount to shift our focus from reactive cleanup to proactive defense. We must prioritize a comprehensive inventory of all network devices and a rigorous patching and end-of-life management program. This should be followed by active threat hunting to identify any existing footholds that Static Tundra may have already established within our environment.

Hunting Controls & Observations

Observing the behaviors of Static Tundra requires a layered approach to telemetry, extending beyond traditional SIEM logs. Security teams should focus on the following data sources to uncover their activity:

  • Endpoint EDR/AV Telemetry: While Static Tundra primarily targets network devices, their activities may result in changes that are visible on endpoints. Look for evidence of compromised user accounts interacting with network devices.
  • Firewall Logs / NetFlow: NetFlow data is critical for this threat. Static Tundra establishes Generic Routing Encapsulation (GRE) tunnels and exfiltrates NetFlow data. Hunt for sudden volumetric changes, new GRE tunnels being established, or unusual traffic flows to external IP addresses. Firewall logs can also show unusual outbound connections that could be indicative of C2.
  • IAM: Static Tundra creates privileged local user accounts for persistence. Monitor for the creation of new, unexpected user accounts, especially on network devices.
  • DNS, Proxy, or Web Gateway Logs: While not the primary C2 channel, these logs may show connections to known Static Tundra infrastructure.
  • Appliance Event Logs: Specifically, on Cisco devices, monitor syslog and AAA (Authentication, Authorization, and Accounting) logs for any changes in configuration, new user creation, or a sudden decrease or gap in logging events, which is a known defense evasion technique.


Additional observations of the attack included the following indicators:

  • Unexpected Smart Install discovery requests.
  • Repeated reload events on routers without admin initiation.
  • Modified firmware images or unsigned IOS binaries.
  • SNMP queries from unusual internal hosts.
  • Outbound network connections initiated by infrastructure devices


MITRE Enterprise ATT&CK Tactics and Techniques

The Static Tundra methodology aligns with several MITRE ATT&CK techniques, focusing on persistence and stealthy data exfiltration rather than noisy, destructive attacks.

Initial Access (TA0001):

  • T1190: Exploiting Public-Facing Application, specifically the CVE-2018-0171 vulnerability in Cisco IOS/IOS XE Smart Install.
  • T1078: Valid Accounts, using compromised or guessed community strings (e.g., “anonymous,” “public”) for SNMP.

Execution (TA0002):

  • T1200: Arbitrary code execution on IOS/IOS XE

Persistence (TA0003):

  • T1136: Create Account, including the creation of privileged local user accounts on network devices.
  • T1542.003: Compromise of Network Device Firmware, through the use of the SYNful Knock implant.
  • T1542.004: Deployment of SYNful Knock firmware implant and bespoke SNMP tooling.

Defense Evasion (TA0005):

  • T1562: Impair Defenses, specifically modifying TACACS+ configurations to hinder remote logging and altering ACLs to permit access from their C2 infrastructure.

Credential Access (TA0006):

  • T1552.004: Harvesting configuration files and credentials from device memory.

Discovery (TA0007):

  • T1016: System Network Configuration Discovery, using native commands like show cdp neighbors to map the internal network without active scanning.

Exfiltration (TA0010):

  • T1048: Exfiltration Over C2 Channel, by redirecting traffic through GRE tunnels and using TFTP/FTP to exfiltrate configurations.
  • T1041: Exfiltration Over Network Medium, specifically by exfiltrating NetFlow data.


Source and Credits

This summary is based on the professional threat intelligence analysis provided by Cisco Talos. The original article is titled "Russian state-sponsored espionage group Static Tundra compromises unpatched end-of-life network devices." The content was last referenced on September 22, 2025.



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