Port 1985HSRP
The Hot Standby Router Protocol (HSRP) is a Cisco proprietary redundancy protocol designed to ensure high network availability by providing automatic failover to a backup router in case the primary router becomes unreachable, thereby maintaining uninterrupted communication within a network..
- transport
- udp
- in transit
- cleartext
- assignment
- official
- risk
- 4/10
- lookups
- 6,339
single transport
payload readable on path
registered with iana
caution
rank 796 of 993 · top 80%
Technical Details
what runs on :1985Cisco’s Hot Standby Router Protocol (HSRP) operates as a first-hop redundancy protocol designed to minimize network downtime caused by router failures. It is primarily used in networks implementing Cisco equipment to enable failover and ensure continuous gateway availability.
HSRP works by configuring a group of routers to present a single virtual IP address and virtual MAC address to hosts on the local subnet. One router is elected as the Active router, while another acts as the Standby router. The Active router handles all routing for the virtual IP address, while the Standby cautiously monitors its status.
Routers in the HSRP group communicate using multicast UDP packets on port 1985, exchanging hello messages to track network status. If the Active router fails, the Standby router takes over nearly instantaneously. Multiple standby routers can be arranged with priorities to determine failover order, enhancing network resilience.
Security Information
exposure of :1985risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
security averages 3.8 across 216 ports — this one sits 0.2 above.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
official
registered with iana for this service — scanners fingerprint it by number
reachable over
udp
udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite
security overview
Common Vulnerabilities:
- HSRP by default lacks authentication, making it susceptible to spoofing attacks where an attacker can send crafted HSRP messages to take over the virtual gateway role (a ‘rogue Active router’).
- Improperly secured HSRP can expose network topology information via multicast status updates, aiding reconnaissance.
- Attackers may cause unnecessary failovers, leading to man-in-the-middle or denial-of-service scenarios.
Common Mitigations:
- Implement HSRP authentication (plain-text or MD5) to verify the identity of routers exchanging HSRP messages.
- Use control plane policing (CoPP) and access control lists (ACLs) to restrict HSRP traffic only to trusted interfaces and devices.
- Limit HSRP hello message propagation across the network using VLAN segmentation and port security.
- Monitor logs and SNMP traps for abnormal HSRP state changes, indicating possible tampering or misconfiguration.
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risk mix of the 8 listed
- caution100%
3 of 8 encrypted