Analytics Story: Cisco Smart Install Remote Code Execution CVE-2018-0171

Date: 2025-08-21 ID: 41178b4d-7dde-4ea6-a886-3e8b5b82fe3b Author: Bhavin Patel, Michael Haag, Splunk Product: Splunk Enterprise Security

Description

This analytic story focuses on detecting exploitation attempts and successful compromises related to CVE-2018-0171, a critical vulnerability in Cisco's Smart Install feature. This vulnerability allows unauthenticated, remote attackers to execute arbitrary code on affected devices or trigger device reloads resulting in denial of service conditions. Recently highlighted by Cisco Talos as being actively exploited by the Russian state-sponsored threat actor "Static Tundra," this vulnerability continues to be a significant threat vector for organizations with unpatched or end-of-life network devices.

Why it matters

The Cisco Smart Install feature vulnerability (CVE-2018-0171) has emerged as a significant threat to network infrastructure security, particularly as it continues to be actively exploited years after patches were released. In August 2025, Cisco Talos revealed that a Russian state-sponsored espionage group dubbed "Static Tundra" has been actively exploiting this seven-year-old vulnerability to compromise unpatched and end-of-life network devices.

The vulnerability exists in the Smart Install feature of Cisco IOS and IOS XE software, which is a plug-and-play configuration and image-management feature that helps customers to deploy new switches. When exploited, CVE-2018-0171 allows unauthenticated remote attackers to execute arbitrary code or cause denial of service conditions by triggering device reloads.

Static Tundra, linked to the FSB's Center 16 unit and possibly associated with the "Energetic Bear" (BERSERK BEAR) threat group, has been observed using this vulnerability since at least 2021. Their attack chain typically begins with exploiting the Smart Install vulnerability to gain initial access, followed by modifying device configurations to enable SNMP with read-write permissions using community strings like "anonymous" and "public." Once access is established, the group employs sophisticated persistence techniques, including the historic SYNful Knock firmware implant (first reported in 2015) and bespoke SNMP tooling to maintain undetected access for multiple years.

The threat actor primarily targets organizations in telecommunications, higher education, and manufacturing sectors across North America, Asia, Africa, and Europe. Their objectives include compromising network devices to gather sensitive configuration information and establishing persistent access for long-term espionage operations aligned with Russian strategic interests.

After gaining initial access, Static Tundra uses various techniques for execution, persistence, defense evasion, discovery, collection, and exfiltration:

They interact with SNMP services using compromised community strings, sometimes spoofing source addresses to bypass access control lists
They leverage SNMP to modify configurations, create privileged local accounts, and establish additional access methods
They use the SYNful Knock firmware implant for persistent access that survives device reboots
They modify TACACS+ configurations to hinder remote logging capabilities
They establish GRE tunnels to redirect traffic to attacker-controlled infrastructure for capture and analysis
They exfiltrate configuration information through various means, including TFTP, FTP, and SNMP connections

While this analytic story focuses on Static Tundra's exploitation of CVE-2018-0171, it's important to note that other state-sponsored actors are likely conducting similar campaigns targeting network devices. Organizations should implement comprehensive security measures, including patching vulnerable devices, disabling Smart Install when not needed, implementing strong authentication mechanisms, and monitoring for suspicious activities related to network device configurations and communications.

Detections

Name ▲▼	Technique ▲▼	Type ▲▼
Cisco Configuration Archive Logging Analysis	Disable or Modify Tools, Account Manipulation, Web Shell	Hunting
Cisco IOS Suspicious Privileged Account Creation	Create Account, Valid Accounts	Anomaly
Cisco Network Interface Modifications	Modify Authentication Process, Remote Services, External Remote Services	Anomaly
Cisco Secure Firewall - Static Tundra Smart Install Abuse	Exploit Public-Facing Application, Exploitation of Remote Services, Endpoint Denial of Service	TTP
Cisco Smart Install Oversized Packet Detection	Exploit Public-Facing Application	TTP
Cisco Smart Install Port Discovery and Status	Exploit Public-Facing Application	TTP
Cisco SNMP Community String Configuration Changes	Disable or Modify Tools, Network Sniffing, Unsecured Credentials	Anomaly
Cisco TFTP Server Configuration for Data Exfiltration	Exfiltration Over Web Service, Data from Local System	TTP

Data Sources

Name ▲▼	Platform ▲▼	Sourcetype ▲▼	Source ▲▼
Cisco IOS Logs	N/A	`cisco:ios`	`cisco:ios`
Cisco Secure Firewall Threat Defense Intrusion Event	N/A	`cisco:sfw:estreamer`	`not_applicable`
Splunk Stream TCP	Splunk	`stream:tcp`	`stream:tcp`

References

Source: GitHub | Version: 1