Cisco IP Phone Remote Code Execution and Denial of Service Vulnerability (CVE-2020-3111)
Published Sources: SingCERT, CVE.org
What is affected, what to do
A vulnerability in the Cisco Discovery Protocol implementation for the Cisco IP Phone could allow an unauthenticated, adjacent attacker to remotely execute code with root privileges or cause a reload of an affected IP phone. The vulnerability is due to missing checks when processing Cisco Discovery Protocol messages.
An exploit is publicly available. Update Cisco IP Conference Phone 7832 Firmware 11.0(4)SR2 to version 12.7\(1\), Cisco IP Conference Phone 7832 With Multiplatform Firmware to version 11.3\(1\)sr1, Cisco IP Conference Phone 8832 Firmware 12.5(1) to version 12.7\(1\).
- Affected
- Cisco IP Conference Phone 7832 Firmware 11.0(4)SR2
lt *..12.7\(1\) - Cisco IP Conference Phone 7832 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Conference Phone 8832 Firmware 12.5(1)
lt *..12.7\(1\) - Cisco IP Conference Phone 8832 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 6821 Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 6841 Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 6851 Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 6861 Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 6871 Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 7811 Firmware 11.0(4)SR2
lt *..12.7\(1\) - Cisco IP Phone 7811 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 7821 Firmware 10.3(1)SR4B
lt *..12.7\(1\) - Cisco IP Phone 7821 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 7841 Firmware 10.3(1)SR4B
lt *..12.7\(1\) - Cisco IP Phone 7841 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 7861 Firmware 9.3(4)SR3
lt *..12.7\(1\) - Cisco IP Phone 7861 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 8811 Firmware 10.3(1)SR4B
lt *..12.7\(1\) - Cisco IP Phone 8811 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 8841 Firmware 9.3(4)SR3
lt *..12.7\(1\) - Cisco IP Phone 8841 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 8851 Firmware 11.0(4)SR2
lt *..12.7\(1\) - Cisco IP Phone 8851 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 8861 Firmware 11.0(4)SR2
lt *..12.7\(1\) - Cisco IP Phone 8861 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 8845 Firmware 11.0(4)SR2
lt *..12.7\(1\) - Cisco IP Phone 8845 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco IP Phone 8865 Firmware 9.3(4)SR3
lt *..12.7\(1\) - Cisco IP Phone 8865 With Multiplatform Firmware
lt *..11.3\(1\)sr1 - Cisco Unified IP Conference Phone 8831 Firmware
lt *..10.3\(1\)sr6 - Cisco Wireless IP Phone 8821 Firmware 9.3(4)SR3
lt *..11.0\(5\)sr2 - Cisco Wireless IP Phone 8821-EX Firmware 9.3(4)SR3
lt *..11.0\(5\)sr2
- Cisco IP Conference Phone 7832 Firmware 11.0(4)SR2
- Fixed in
- Cisco IP Conference Phone 7832 Firmware 11.0(4)SR2
12.7\(1\) - Cisco IP Conference Phone 7832 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Conference Phone 8832 Firmware 12.5(1)
12.7\(1\) - Cisco IP Conference Phone 8832 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 6821 Firmware
11.3\(1\)sr1 - Cisco IP Phone 6841 Firmware
11.3\(1\)sr1 - Cisco IP Phone 6851 Firmware
11.3\(1\)sr1 - Cisco IP Phone 6861 Firmware
11.3\(1\)sr1 - Cisco IP Phone 6871 Firmware
11.3\(1\)sr1 - Cisco IP Phone 7811 Firmware 11.0(4)SR2
12.7\(1\) - Cisco IP Phone 7811 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 7821 Firmware 10.3(1)SR4B
12.7\(1\) - Cisco IP Phone 7821 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 7841 Firmware 10.3(1)SR4B
12.7\(1\) - Cisco IP Phone 7841 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 7861 Firmware 9.3(4)SR3
12.7\(1\) - Cisco IP Phone 7861 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 8811 Firmware 10.3(1)SR4B
12.7\(1\) - Cisco IP Phone 8811 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 8841 Firmware 9.3(4)SR3
12.7\(1\) - Cisco IP Phone 8841 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 8851 Firmware 11.0(4)SR2
12.7\(1\) - Cisco IP Phone 8851 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 8861 Firmware 11.0(4)SR2
12.7\(1\) - Cisco IP Phone 8861 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 8845 Firmware 11.0(4)SR2
12.7\(1\) - Cisco IP Phone 8845 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco IP Phone 8865 Firmware 9.3(4)SR3
12.7\(1\) - Cisco IP Phone 8865 With Multiplatform Firmware
11.3\(1\)sr1 - Cisco Unified IP Conference Phone 8831 Firmware
10.3\(1\)sr6 - Cisco Wireless IP Phone 8821 Firmware 9.3(4)SR3
11.0\(5\)sr2 - Cisco Wireless IP Phone 8821-EX Firmware 9.3(4)SR3
11.0\(5\)sr2
- Cisco IP Conference Phone 7832 Firmware 11.0(4)SR2
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Metrics
8.8
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
8.8
CVSS v3
Severity High on the scale from 0 to 10.
Source: SingCERT, CVE.org
3.1 %
EPSS score
Moderate — model estimates 1-10% exploitation likelihood.
Source: FIRST EPSS, percentile 87.8
Show all metrics
- Severity
- High
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 105.63 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- PoC (publicly reported)
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 8.8 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 8.8
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 3.1 %
- Moderate — model estimates 1-10% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 87.8
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: none known · not automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 15 November 2024
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-20
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
A vulnerability in the Cisco Discovery Protocol implementation for the Cisco IP Phone could allow an unauthenticated, adjacent attacker to remotely execute code with root privileges or cause a reload of an affected IP phone. The vulnerability is due to missing checks when processing Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a crafted Cisco Discovery Protocol packet to the targeted IP phone. A successful exploit could allow the attacker to remotely execute code with root privileges or cause a reload of an affected IP phone, resulting in a denial of service (DoS) condition. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).
Source: CSA/SingCERT, NVD (NIST), cvelistv5
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Cisco | Cisco IP phone |
|
|
Vendors and products
- Cisco Cisco IP Conference Phone 7832 Firmware 9.3(4)SR3
- Cisco IP Conference Phone 7832 With Multiplatform Firmware
- Cisco Cisco IP Conference Phone 8832 Firmware 11.0(4)SR2
- Cisco IP Conference Phone 8832 With Multiplatform Firmware
- Cisco IP Phone 6841 Firmware
- Cisco IP Phone 6851 Firmware
- Cisco IP Phone 6861 Firmware
- Cisco IP Phone 6871 Firmware
- Cisco Cisco IP Phone 7811 Firmware 10.3(1)SR4B
- Cisco IP Phone 7811 With Multiplatform Firmware
- Cisco Cisco IP Phone 7821 Firmware 10.3(1)SR4B
- Cisco IP Phone 7821 With Multiplatform Firmware
Affected operating systems
| Other | cisco | ip_conference_phone_7832_firmware | — |
| Other | cisco | ip_conference_phone_7832_with_multiplatform_firmware | — |
| Other | cisco | ip_conference_phone_8832_firmware | — |
| Other | cisco | ip_conference_phone_8832_with_multiplatform_firmware | — |
| Other | cisco | ip_phone_6821_firmware | — |
| Other | cisco | ip_phone_6841_firmware | — |
| Other | cisco | ip_phone_6851_firmware | — |
| Other | cisco | ip_phone_6861_firmware | — |
| Other | cisco | ip_phone_6871_firmware | — |
| Other | cisco | ip_phone_7811_firmware | — |
| Other | cisco | ip_phone_7811_with_multiplatform_firmware | — |
| Other | cisco | ip_phone_7821_firmware | — |
| Other | cisco | ip_phone_7821_with_multiplatform_firmware | — |
| Other | cisco | ip_phone_7841_firmware | — |
| Other | cisco | ip_phone_7841_with_multiplatform_firmware | — |
| Other | cisco | ip_phone_7861_firmware | — |
| Other | cisco | ip_phone_7861_with_multiplatform_firmware | — |
| Other | cisco | ip_phone_8811_firmware | — |
| Other | cisco | ip_phone_8811_with_multiplatform_firmware | — |
| Other | cisco | ip_phone_8841_firmware | — |
| Other | cisco | ip_phone_8841_with_multiplatform_firmware | — |
| Other | cisco | ip_phone_8845_firmware | — |
| Other | cisco | ip_phone_8845_with_multiplatform_firmware | — |
| Other | cisco | ip_phone_8851_firmware | — |
Weakness classes (CWE)
CWE-20Improper Input Validation
Class
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Entry at MITRE CWE-20
Public exploit references
Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.
| Packet Storm | Cisco Discovery Protocol CDP Remote Device Takeover (opens in a new tab)packetstormsecurity.com | PoC (publicly reported)reported, not verified | — |
References & sources
- tools.cisco.com20200205 Cisco IP Phone Remote Code Execution and Denial of Service VulnerabilityVendor advisory, x_refsource_CISCO, Vendor advisory
- packetstormsecurity.comfiles/156203/Cisco-Discovery-Protocol-CDP-Remote-Device-Takeove…x_refsource_MISC, Third-party advisory, Vulnerability database
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<a href="https://intel.neosec.eu/en/cve/CVE-2020-3111"><img src="https://intel.neosec.eu/badge/cve/CVE-2020-3111.svg?lang=en" alt="CVE-2020-3111 – NEOSEC Intel" height="20"></a>