Rack vulnerable to ReDoS in content type parsing (2nd degree polynomial)

Summary

module Rack
  class MediaType
    SPLIT_PATTERN = %r{\s*[;,]\s*}

The above regexp is subject to ReDos. 50K blank characters as a prefix to the header will take over 10s to split.

PoC

A simple HTTP request with lots of blank characters in the content-type header:

request["Content-Type"] = (" " * 50_000) + "a,"

Impact

It's a very easy to craft ReDoS. Like all ReDoS the impact is debatable.

Rack Header Parsing leads to Possible Denial of Service Vulnerability

Possible Denial of Service Vulnerability in Rack Header Parsing

There is a possible denial of service vulnerability in the header parsing routines in Rack. This vulnerability has been assigned the CVE identifier CVE-2024-26146.

Versions Affected: All. Not affected: None Fixed Versions: 2.0.9.4, 2.1.4.4, 2.2.8.1, 3.0.9.1

Impact

Carefully crafted headers can cause header parsing in Rack to take longer than expected resulting in a possible denial of service issue. Accept and Forwarded headers are impacted.

Ruby 3.2 has mitigations for this problem, so Rack applications using Ruby 3.2 or newer are unaffected.

Releases

The fixed releases are available at the normal locations.

Workarounds

There are no feasible workarounds for this issue.

Patches

To aid users who aren't able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

• 2-0-header-redos.patch - Patch for 2.0 series
• 2-1-header-redos.patch - Patch for 2.1 series
• 2-2-header-redos.patch - Patch for 2.2 series
• 3-0-header-redos.patch - Patch for 3.0 series

Credits

Thanks to svalkanov for reporting this and providing patches!

Possible Log Injection in Rack::CommonLogger

Summary

Rack::CommonLogger can be exploited by crafting input that includes newline characters to manipulate log entries. The supplied proof-of-concept demonstrates injecting malicious content into logs.

Details

When a user provides the authorization credentials via Rack::Auth::Basic, if success, the username will be put in env['REMOTE_USER'] and later be used by Rack::CommonLogger for logging purposes.

The issue occurs when a server intentionally or unintentionally allows a user creation with the username contain CRLF and white space characters, or the server just want to log every login attempts. If an attacker enters a username with CRLF character, the logger will log the malicious username with CRLF characters into the logfile.

Impact

Attackers can break log formats or insert fraudulent entries, potentially obscuring real activity or injecting malicious data into log files.

Mitigation

• Update to the latest version of Rack.

Local File Inclusion in Rack::Static

Summary

Rack::Static can serve files under the specified root: even if urls: are provided, which may expose other files under the specified root: unexpectedly.

Details

The vulnerability occurs because Rack::Static does not properly sanitize user-supplied paths before serving files. Specifically, encoded path traversal sequences are not correctly validated, allowing attackers to access files outside the designated static file directory.

Impact

By exploiting this vulnerability, an attacker can gain access to all files under the specified root: directory, provided they are able to determine then path of the file.

Mitigation

• Update to the latest version of Rack, or
• Remove usage of Rack::Static, or
• Ensure that root: points at a directory path which only contains files which should be accessed publicly.

It is likely that a CDN or similar static file server would also mitigate the issue.

Escape Sequence Injection vulnerability in Rack lead to Possible Log Injection

Summary

Rack::Sendfile can be exploited by crafting input that includes newline characters to manipulate log entries.

Details

The Rack::Sendfile middleware logs unsanitized header values from the X-Sendfile-Type header. An attacker can exploit this by injecting escape sequences (such as newline characters) into the header, resulting in log injection.

Impact

This vulnerability can distort log files, obscure attack traces, and complicate security auditing.

Mitigation

• Update to the latest version of Rack, or
• Remove usage of Rack::Sendfile.

Rack has an Unbounded-Parameter DoS in Rack::QueryParser

Summary

Rack::QueryParser parses query strings and application/x-www-form-urlencoded bodies into Ruby data structures without imposing any limit on the number of parameters, allowing attackers to send requests with extremely large numbers of parameters.

Details

The vulnerability arises because Rack::QueryParser iterates over each &-separated key-value pair and adds it to a Hash without enforcing an upper bound on the total number of parameters. This allows an attacker to send a single request containing hundreds of thousands (or more) of parameters, which consumes excessive memory and CPU during parsing.

Impact

An attacker can trigger denial of service by sending specifically crafted HTTP requests, which can cause memory exhaustion or pin CPU resources, stalling or crashing the Rack server. This results in full service disruption until the affected worker is restarted.

Mitigation

• Update to a version of Rack that limits the number of parameters parsed, or
• Use middleware to enforce a maximum query string size or parameter count, or
• Employ a reverse proxy (such as Nginx) to limit request sizes and reject oversized query strings or bodies.

Limiting request body sizes and query string lengths at the web server or CDN level is an effective mitigation.

Rack has possible DoS Vulnerability with Range Header

Possible DoS Vulnerability with Range Header in Rack

There is a possible DoS vulnerability relating to the Range request header in Rack. This vulnerability has been assigned the CVE identifier CVE-2024-26141.

Versions Affected: >= 1.3.0. Not affected: < 1.3.0 Fixed Versions: 3.0.9.1, 2.2.8.1

Impact

Carefully crafted Range headers can cause a server to respond with an unexpectedly large response. Responding with such large responses could lead to a denial of service issue.

Vulnerable applications will use the Rack::File middleware or the Rack::Utils.byte_ranges methods (this includes Rails applications).

Releases

The fixed releases are available at the normal locations.

Workarounds

There are no feasible workarounds for this issue.

Patches

To aid users who aren't able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

• 3-0-range.patch - Patch for 3.0 series
• 2-2-range.patch - Patch for 2.2 series

Credits

Thank you ooooooo_q for the report and patch

Denial of Service Vulnerability in Rack Content-Type Parsing

There is a possible denial of service vulnerability in the content type parsing component of Rack. This vulnerability has been assigned the CVE identifier CVE-2024-25126.

Versions Affected: >= 0.4 Not affected: < 0.4 Fixed Versions: 3.0.9.1, 2.2.8.1

Impact

Carefully crafted content type headers can cause Rack’s media type parser to take much longer than expected, leading to a possible denial of service vulnerability.

Impacted code will use Rack’s media type parser to parse content type headers. This code will look like below:

request.media_type

## OR
request.media_type_params

## OR
Rack::MediaType.type(content_type)

Some frameworks (including Rails) call this code internally, so upgrading is recommended!

All users running an affected release should either upgrade or use one of the workarounds immediately.

Releases

The fixed releases are available at the normal locations.

Workarounds

There are no feasible workarounds for this issue.

Possible DoS Vulnerability with Range Header in Rack

There is a possible DoS vulnerability relating to the Range request header in Rack. This vulnerability has been assigned the CVE identifier CVE-2024-26141.

Versions Affected: >= 1.3.0. Not affected: < 1.3.0 Fixed Versions: 3.0.9.1, 2.2.8.1

Impact

Carefully crafted Range headers can cause a server to respond with an unexpectedly large response. Responding with such large responses could lead to a denial of service issue.

Vulnerable applications will use the Rack::File middleware or the Rack::Utils.byte_ranges methods (this includes Rails applications).

Releases

The fixed releases are available at the normal locations.

Workarounds

There are no feasible workarounds for this issue.

Possible Denial of Service Vulnerability in Rack Header Parsing

There is a possible denial of service vulnerability in the header parsing routines in Rack. This vulnerability has been assigned the CVE identifier CVE-2024-26146.

Versions Affected: All. Not affected: None Fixed Versions: 2.0.9.4, 2.1.4.4, 2.2.8.1, 3.0.9.1

Impact

Carefully crafted headers can cause header parsing in Rack to take longer than expected resulting in a possible denial of service issue. Accept and Forwarded headers are impacted.

Ruby 3.2 has mitigations for this problem, so Rack applications using Ruby 3.2 or newer are unaffected.

Releases

The fixed releases are available at the normal locations.

Workarounds

There are no feasible workarounds for this issue.