CVE-2013-0183 in Rack
Summary
by MITRE
multipart/parser.rb in Rack 1.3.x before 1.3.8 and 1.4.x before 1.4.3 allows remote attackers to cause a denial of service (memory consumption and out-of-memory error) via a long string in a Multipart HTTP packet.
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Analysis
by VulDB Data Team • 12/29/2021
The vulnerability identified as CVE-2013-0183 represents a critical denial of service weakness within the Rack web application framework that affected versions prior to 1.3.8 and 1.4.3. This issue specifically targets the multipart/parser.rb component responsible for parsing multipart HTTP requests commonly used for file uploads and form submissions in web applications. The flaw manifests when the framework processes malformed multipart data containing excessively long strings, leading to abnormal memory consumption patterns that can ultimately result in system out-of-memory conditions.
The technical root cause of this vulnerability lies in the insufficient input validation and memory management within the multipart parsing logic. When a malicious attacker crafts a specially designed HTTP request with an abnormally long string within a multipart boundary, the Rack parser attempts to process and store this data in memory without adequate bounds checking. This processing behavior causes the application to consume excessive memory resources proportional to the length of the malformed string, creating a memory exhaustion condition that can crash the application or render it unresponsive to legitimate requests. The vulnerability operates at the application layer and can be exploited through standard HTTP communication channels without requiring authentication or special privileges.
The operational impact of CVE-2013-0183 extends beyond simple service disruption to potentially compromise the availability of entire web applications built on the affected Rack versions. Attackers can leverage this vulnerability to launch denial of service attacks against web servers, applications, or entire hosting environments by sending carefully crafted multipart requests that trigger the memory consumption bug. This weakness is particularly dangerous in shared hosting environments or applications with limited memory resources where a single malicious request can bring down the entire service. The vulnerability affects any application using the affected Rack versions regardless of the specific web framework or application stack, making it a widespread concern across the ruby web development ecosystem.
Organizations should immediately upgrade to Rack versions 1.3.8 or 1.4.3 and later to mitigate this vulnerability, as these releases contain the necessary patches to properly validate multipart data and prevent excessive memory allocation. Additional mitigations include implementing rate limiting on file upload endpoints, configuring proper input validation at the application level, and monitoring for unusual memory consumption patterns. From a cybersecurity perspective, this vulnerability aligns with CWE-770, which addresses allocation of resources without limits or with inadequate limits, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. System administrators should also consider implementing intrusion detection systems that can identify and block suspicious multipart request patterns to provide additional defense in depth against exploitation attempts.