Authentication Bypass via URL Tokens in Capgo Console

Executive Summary

The vulnerability exists in Capgo console.capgo.app/login versions before 12.128.2, where the application accepts access_token and refresh_token in URL query parameters and automatically authenticates users without any confirmation.

This allows attackers to craft malicious links that force victims into attacker-controlled sessions, exposing sensitive tokens in browser history and logs.

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Detection Guidance

This vulnerability can be detected by monitoring network traffic and logs for URLs containing access_token and refresh_token parameters in query strings directed to console.capgo.app/login.

You can use commands to search for such URLs in web server logs or network captures. For example, using grep on log files:

• grep -i 'access_token=' /path/to/access.log
• grep -i 'refresh_token=' /path/to/access.log

Additionally, network packet captures can be filtered with tools like tcpdump or Wireshark to detect HTTP requests containing these tokens in the URL query parameters.

• tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep 'access_token='

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Impact Analysis

This vulnerability can lead to unauthorized access to user accounts because attackers can trick users into clicking malicious links that automatically authenticate them into attacker-controlled sessions.

Additionally, sensitive tokens are exposed in browser history and logs, increasing the risk of token theft and session hijacking.

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Compliance Impact

This vulnerability exposes sensitive authentication tokens in browser history and logs, which can lead to unauthorized access and session hijacking.

Such exposure of sensitive information can conflict with compliance requirements in standards and regulations like GDPR and HIPAA, which mandate protection of personal and sensitive data to prevent unauthorized access and data breaches.

By allowing attackers to force victims into attacker-controlled sessions and exposing tokens in logs, the vulnerability increases the risk of data compromise, potentially violating data protection and privacy obligations under these regulations.

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Mitigation Strategies

The immediate mitigation step is to upgrade Capgo to version 12.128.2 or later, where this vulnerability has been patched.

Until the upgrade can be applied, avoid using or sharing URLs that contain access_token and refresh_token in query parameters.

Additionally, configure monitoring to detect and block requests that include these tokens in URL query strings.

The recommended long-term fix is to ensure the application does not accept authentication tokens via URL query parameters and requires explicit user confirmation before setting sessions.

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