From 50e4fa39cf51b8a9bbe39ccd25b29470bebe7c3c Mon Sep 17 00:00:00 2001
From: HackTricks News Bot <bot@hacktricks.xyz>
Date: Thu, 12 Mar 2026 16:52:25 +0000
Subject: [PATCH] Add content from: Research Update Enhanced
 src/generic-methodologies-and-resou...

---
 .../pentesting-network/eigrp-attacks.md       | 38 ++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/src/generic-methodologies-and-resources/pentesting-network/eigrp-attacks.md b/src/generic-methodologies-and-resources/pentesting-network/eigrp-attacks.md
index bb64aa79696..7ac66469eef 100644
--- a/src/generic-methodologies-and-resources/pentesting-network/eigrp-attacks.md
+++ b/src/generic-methodologies-and-resources/pentesting-network/eigrp-attacks.md
@@ -4,6 +4,14 @@
 
 **This is a summary of the attacks exposed in** [**https://medium.com/@in9uz/cisco-nightmare-pentesting-cisco-networks-like-a-devil-f4032eb437b9**](https://medium.com/@in9uz/cisco-nightmare-pentesting-cisco-networks-like-a-devil-f4032eb437b9). Check it for further information.
 
+
+## Protocol Notes Useful for Attacks
+
+- EIGRP uses five packet types to handle session management and DUAL messaging: **HELLO/ACK**, **QUERY** (includes SIA-QUERY), **REPLY** (includes SIA-REPLY), **REQUEST**, and **UPDATE**.
+- DUAL message types are **UPDATE**, **QUERY**, and **REPLY**. When a route stays **ACTIVE** too long, EIGRP uses **SIA-QUERY/SIA-REPLY** to probe neighbors before declaring the route stuck-in-active.
+- EIGRP relies on **TLVs** (Parameter, Authentication, Sequence, Software Version, Route TLVs). If authentication TLVs are present (MD5/SHA2), forged packets must carry valid auth data to be accepted.
+
+
 ## **Fake EIGRP Neighbors Attack**
 
 - **Objective**: To overload router CPUs by flooding them with EIGRP hello packets, potentially leading to a Denial of Service (DoS) attack.
@@ -58,7 +66,35 @@
   - `--as`: Defines the EIGRP AS number.
   - `--src`: Sets the attacker’s IP address.
 
-{{#include ../../banners/hacktricks-training.md}}
 
+## **SIA / Query Exhaustion (DoS)**
+
+- **Objective**: Force neighbors into **Stuck-in-Active (SIA)** by driving routes ACTIVE and preventing timely REPLYs, causing adjacency resets and route loss.
+- **High-level idea**: Inject or perturb many prefixes so neighbors enter ACTIVE and issue QUERYs, then prevent/blackhole REPLYs so the SIA timer expires; repeat to keep the domain unstable and CPU-bound.
+
+## **Packet Crafting with Scapy**
+
+Scapy ships an EIGRP contrib layer (`scapy.contrib.eigrp`) with common TLVs (Parameter, Auth, Internal/External Route). You can build custom packets for lab validation or controlled injection.
+
+```python
+from scapy.all import IP, send
+from scapy.contrib.eigrp import EIGRP, EIGRPParam, EIGRPSwVer, EIGRPIntRoute
+
+pkt = IP(dst="10.0.0.1")/EIGRP(asn=1, tlvlist=[
+    EIGRPParam(k1=1, k3=1, holdtime=15),
+    EIGRPSwVer(),
+    EIGRPIntRoute(dst="10.10.10.0", prefixlen=24, nexthop="10.0.0.2"),
+])
+
+# Set the correct opcode for the packet type you need (UPDATE/QUERY/REPLY) before sending.
+send(pkt, iface="eth0")
+```
+
+## References
+
+- [https://datatracker.ietf.org/doc/html/rfc7868](https://datatracker.ietf.org/doc/html/rfc7868)
+- [https://scapy.readthedocs.io/en/latest/api/scapy.contrib.eigrp.html](https://scapy.readthedocs.io/en/latest/api/scapy.contrib.eigrp.html)
+
+{{#include ../../banners/hacktricks-training.md}}