CDPwn: Cisco Discovery Protocol Vulnerabilities Disclosed by Researchers
Researchers find several flaws in a proprietary protocol used by many Cisco devices.
背景說明
On February 5, researchers at Armis Security announced their discovery of five vulnerabilities in the Cisco Discovery Protocol, a proprietary protocol designed to allow for discovery and communication between Cisco devices.
分析
CDPwn is a series of vulnerabilities in Cisco Discovery Protocol due to improper validation of Cisco Discovery Protocol messages. By sending a specially crafted packet to a vulnerable device, an unauthenticated, adjacent attacker could achieve remote code execution or create a denial of service condition.
Cisco notes in their advisories that because Cisco Discovery Protocol is a Layer 2 protocol, an attacker “must be in the same broadcast domain as the affected device.”
The following are the five vulnerabilities disclosed by Armis:
| CVE | 職稱 | CVSSv3 |
|---|---|---|
| CVE-2020-3110 | Cisco Video Surveillance 8000 Series IP Cameras Cisco Discovery Protocol Remote Code Execution and Denial of Service Vulnerability | 8.8 |
| CVE-2020-3111 | Cisco IP Phone Remote Code Execution and Denial of Service Vulnerability | 8.8 |
| CVE-2020-3118 | Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability | 8.8 |
| CVE-2020-3119 | Cisco NX-OS Software Cisco Discovery Protocol Remote Code Execution Vulnerability | 8.8 |
| CVE-2020-3120 | Cisco FXOS, IOS XR, and NX-OS Software Cisco Discovery Protocol Denial of Service Vulnerability | 7.4 |
According to Armis, these vulnerabilities “affect tens of million devices” including Cisco NX-OS switches, Cisco IOS XR routers, Cisco NCS Systems, Cisco 8000 IP Cameras, Cisco Firepower Firewalls, and Cisco IP Phone 7800 and 8800 Series.
Exploitation requires the Cisco Discovery Protocol to be enabled and Cisco notes that it is enabled by default on certain devices using NX-OS and FXOS, though it is not enabled by default on routers using Cisco IOS XR.
概念驗證
At the time this blog post was published, there was no proof-of-concept code for any of the CDPwn vulnerabilities disclosed by Armis.
解決方法
Cisco has released software updates to address these vulnerabilities. They’ve identified a list of vulnerable and not vulnerable products. The list below contains links to the respective section of each advisory that identifies vulnerable products.
找出受影響的系統
A list of Tenable plugins to identify these vulnerabilities will appear here as they’re released.
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Satnam Narang
安全應變資深研發工程師
Satnam 於 2018 年加入 Tenable 公司。他在業界擁有 15 年的豐富經驗 (M86 Security 和賽門鐵克)。 他對於防網路釣魚工作小組 (Anti-Phishing Working Group) 多所貢獻，協助美國國家網路安全聯盟 (National Cyber Security Alliance) 開發一份社群網路指南 (Social Networking Guide)，並且揭露了一個 Twitter 上的龐大垃圾郵件 botnet，同時也是第一個提報 Tinder 上垃圾郵件機器人的人。他還曾出現在 NBC 夜線新聞、Entertainment Tonight、Bloomberg West 以及 Why Oh Why 播客中。
他在工作之餘的興趣：Satnam 喜歡寫詩和創作嘻哈音樂。他喜歡參加現場音樂表演、和他 3 個姪女做伴、足球、藍球、看寶萊塢電影、玩音樂以及 Grogu (尤達寶寶)。
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