Published Monday, June 29, 2026 at 01:10 PM PT

BLUF: Russian state-sponsored threat actor APT28 is actively exploiting vulnerable routers to hijack DNS and conduct adversary-in-the-middle (AiTM) attacks, enabling theft of passwords and authentication tokens. All organisations operating internet-facing or edge routers should treat this as an active threat requiring immediate review.
DETAILS
- APT28 (also known as Fancy Bear; attributed to Russian military intelligence, GRU) is exploiting vulnerable routers to manipulate DNS resolution, redirecting traffic through attacker-controlled infrastructure.
- The attack methodology enables AiTM positioning, allowing APT28 to intercept, inspect, and modify network traffic without detection by end users.
- Confirmed objectives include credential theft โ specifically passwords and authentication tokens โ which can enable follow-on intrusions into enterprise and government networks.
- The UK National Cyber Security Centre (NCSC) has published a formal advisory on this activity; the advisory is co-attributed, suggesting involvement of additional Five Eyes partner agencies (specific co-signatories not confirmed in source material at time of writing).
- This activity is consistent with APT28’s established pattern of targeting network infrastructure as an initial access vector, as previously observed in campaigns against Cisco and other edge devices.
IMPACT
- Who is affected: Any organisation operating routers with unpatched firmware, default credentials, or exposed management interfaces โ particularly government, defence, critical national infrastructure, and private sector entities in NATO-aligned countries.
- Scope: Network-wide. Successful DNS hijacking affects all devices routing traffic through a compromised router, regardless of endpoint security posture.
- Data at risk: Credentials, session tokens, and potentially any unencrypted or improperly validated traffic transiting affected infrastructure.
- Broader context: UK NCSC has previously noted hostile states are linked to approximately three-quarters of cyber attacks affecting UK critical systems โ this advisory is consistent with that threat picture.
RECOMMENDED ACTIONS
- Audit all routers immediately โ identify firmware versions, check for available patches, and apply updates without delay.
- Disable remote management interfaces where not operationally required; restrict access to trusted IPs only.
- Rotate credentials for all network devices and any accounts whose traffic may have transited potentially compromised infrastructure.
- Review DNS configurations on edge devices for unauthorised modifications; compare against known-good baselines.
- Inspect authentication logs for anomalous token usage or credential reuse indicative of AiTM interception.
- Consult the full NCSC advisory at ncsc.gov.uk for specific indicators of compromise (IoCs) and technical mitigations.
SOURCES
- UK NCSC News Advisory: APT28 exploit routers to enable DNS hijacking operations โ ncsc.gov.uk
- UK NCSC All Resources: APT28 exploit routers to enable DNS hijacking operations
โ UNCERTAINTY FLAG: Specific router models, CVE identifiers, and co-authoring agencies for this advisory are not confirmed in available source material. Consult the full NCSC publication for technical specifics before scoping your response.
