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Unified Threat Defense Snort Intrusion Prevention System Engine CVE-2024-20508

MEDIUM
Heap-based Buffer Overflow (CWE-122)
2024-09-25 psirt@cisco.com
6.5
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Heap buffer bounds checking
MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 6.5 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAI

A vulnerability in Cisco Unified Threat Defense (UTD) Snort Intrusion Prevention System (IPS) Engine for Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass configured. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-122. A vulnerability in Cisco Unified Threat Defense (UTD) Snort Intrusion Prevention System (IPS) Engine for Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass configured security policies or cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient validation of HTTP requests when they are processed by Cisco UTD Snort IPS Engine. An attacker could exploit this vulnerability by sending a crafted HTTP request through an affected device. A successful exploit could allow the attacker to trigger a reload of the Snort process. If the action in case of Cisco UTD Snort IPS Engine failure is set to the default, fail-open, successful exploitation of this vulnerability could allow the attacker to bypass configured security policies. If the action in case of Cisco UTD Snort IPS Engine failure is set to fail-close, successful exploitation of this vulnerability could cause traffic that is configured to be inspected by Cisco UTD Snort IPS Engine to be dropped. Affected products include: Cisco Unified Threat Defense Snort Intrusion Prevention System Engine.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low

DescriptionNVD

A vulnerability in Cisco Unified Threat Defense (UTD) Snort Intrusion Prevention System (IPS) Engine for Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass configured security policies or cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to insufficient validation of HTTP requests when they are processed by Cisco UTD Snort IPS Engine. An attacker could exploit this vulnerability by sending a crafted HTTP request through an affected device. A successful exploit could allow the attacker to trigger a reload of the Snort process. If the action in case of Cisco UTD Snort IPS Engine failure is set to the default, fail-open, successful exploitation of this vulnerability could allow the attacker to bypass configured security policies. If the action in case of Cisco UTD Snort IPS Engine failure is set to fail-close, successful exploitation of this vulnerability could cause traffic that is configured to be inspected by Cisco UTD Snort IPS Engine to be dropped.

Threat Intelligence Overview

EPSS Score
0.4%
Top 66% exploitable
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

A heap overflow occurs when a program writes data beyond the bounds of a buffer allocated in the heap memory region.

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.6.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.6.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.6.6:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.7.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.7.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.8.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.9.5a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.11.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.12.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.12.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.12.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.12.3a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.12.4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.13.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.14.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_threat_defense_snort_intrusion_prevention_system_engine:17.15.1a:*:*:*:*:*:*:*
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