Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2021-32727— End-to-end encryption device setup did not verify public key

Quick assessment

Affected
nextcloud security-advisories
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Nextcloud是德国Nextcloud公司的一套开源的自托管文件同步和共享的通信应用平台。 Nextcloud Android Client在3.16.1之前版本存在信任管理问题漏洞，该漏洞源于Nextcloud Android客户端跳过了一个涉及客户端检查私钥是否属于之前下载的公共证书的步骤。如果Nextcloud实例提供了一个恶意公钥，那么数据将为此密钥进行加密，从而可以被恶意参与者访问。

CVSS 5.7 · Medium EPSS 0.73% · P53

Possible ATT&CK Techniques 2 AI

T1042 T1557 · Adversary-in-the-Middle
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2021-32727

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
End-to-end encryption device setup did not verify public key
Source: CVE Program / CVE List V5
Vulnerability Description
Nextcloud Android Client is the Android client for Nextcloud. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
证书验证不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Nextcloud 信任管理问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Nextcloud是德国Nextcloud公司的一套开源的自托管文件同步和共享的通信应用平台。 Nextcloud Android Client在3.16.1之前版本存在信任管理问题漏洞，该漏洞源于Nextcloud Android客户端跳过了一个涉及客户端检查私钥是否属于之前下载的公共证书的步骤。如果Nextcloud实例提供了一个恶意公钥，那么数据将为此密钥进行加密，从而可以被恶意参与者访问。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
nextcloud security-advisories < 3.16.1 -

II. Public POCs for CVE-2021-32727

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2021-32727

请登录查看更多情报信息。

Patches & Fixes for CVE-2021-32727 (1)

Vendor Advisories for CVE-2021-32727 (1)

Other References for CVE-2021-32727 (2)

Same Patch Batch · nextcloud · 2021-07-12 · 14 CVEs total

CVE-2021-32688 8.8 HIGH Application specific tokens can change their own scope
CVE-2021-32689 8.1 HIGH Nextcloud Talk not properly disassociating users from chats after account deletion
CVE-2021-32726 7.1 HIGH Webauthn tokens not removed after user has been deleted
CVE-2021-32741 5.3 MEDIUM Lack of ratelimit on public share link mount endpoint
CVE-2021-32705 5.3 MEDIUM Lack of ratelimit on public DAV endpoint
CVE-2021-32703 5.3 MEDIUM Lack of ratelimit on shareinfo endpoint
CVE-2021-32733 4.8 MEDIUM XSS in Nextcloud Text application
CVE-2021-32707 4.3 MEDIUM Bypass of image blocking in Nextcloud Mail
CVE-2021-32678 3.7 LOW Ratelimit not applied on OCS API responses
CVE-2021-32725 3.5 LOW Default share permissions not respected for federated reshares
CVE-2021-32679 3.5 LOW Filenames not escaped by default in controllers using DownloadResponse
CVE-2021-32680 3.3 LOW Audit log is not properly logging unsetting of share expiration date
CVE-2021-32734 3.1 LOW File path disclosure of shared files in Nextcloud Text application

IV. Related Vulnerabilities

Same product: security-advisories
Same vendor: nextcloud
Same weakness: CWE-295

V. Comments for CVE-2021-32727

No comments yet

Leave a comment