Executive Summary

CVE-2021-47935 is a remote code execution vulnerability found in Sentry version 8.2.0 and earlier. It allows authenticated superusers to execute arbitrary commands by injecting malicious pickle-serialized objects through the audit log entry data parameter.

Attackers exploit this vulnerability by sending specially crafted POST requests to the admin audit log endpoint. These requests contain base64-encoded compressed pickle payloads in the data field, which when processed, lead to code execution with the application's privileges.

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Impact Analysis

This vulnerability can have severe impacts because it allows an authenticated superuser to execute arbitrary code on the server running Sentry with the application's privileges.

• Attackers can gain control over the application environment, potentially leading to data theft, data manipulation, or disruption of services.
• Since the code execution occurs with application privileges, it may allow attackers to escalate their access or move laterally within the network.
• This can compromise the integrity, confidentiality, and availability of the affected system and any data it processes.

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Detection Guidance

This vulnerability can be detected by monitoring for suspicious POST requests to the admin audit log endpoint that contain base64-encoded compressed pickle payloads in the data field. Such requests are indicative of attempts to inject malicious pickle-serialized objects.

To detect exploitation attempts on your system, you can use network monitoring or web server logs to search for POST requests targeting the audit log endpoint with unusual or encoded payloads.

• Use tools like tcpdump or Wireshark to capture network traffic and filter for POST requests to the admin audit log endpoint.
• Use grep or similar commands on web server logs to find POST requests containing base64-encoded data fields, for example: grep -i 'POST /api/0/organizations/.*/auditlog/' /var/log/nginx/access.log | grep -Eo 'data=[A-Za-z0-9+/=]+'
• Inspect application logs for audit log entries with suspicious or malformed data parameters that could indicate pickle payload injection.

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Mitigation Strategies

Immediate mitigation steps include restricting access to the admin audit log endpoint to only trusted authenticated superusers, as the vulnerability requires authenticated superuser privileges.

Additionally, consider applying any available patches or updates from the vendor that address this vulnerability.

If patching is not immediately possible, monitor and block suspicious POST requests containing base64-encoded pickle payloads targeting the audit log endpoint.

Review and tighten authentication and authorization controls to prevent unauthorized access to sensitive endpoints.

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Compliance Impact

The vulnerability in Sentry 8.2.0 allows authenticated superusers to execute arbitrary code with application privileges by injecting malicious pickle-serialized objects. This remote code execution flaw can lead to unauthorized access and control over the application environment.

Such unauthorized code execution risks compromising sensitive data and system integrity, which can negatively impact compliance with data protection regulations like GDPR and HIPAA that require strict controls over data confidentiality, integrity, and access.

If exploited, this vulnerability could lead to data breaches or unauthorized data manipulation, potentially resulting in violations of these standards and associated legal and financial consequences.

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