CVE-2013-1753 in Python
Summary
by MITRE
The gzip_decode function in the xmlrpc client library in Python 3.4 and earlier allows remote attackers to cause a denial of service (memory consumption) via a crafted HTTP request.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability identified as CVE-2013-1753 resides within Python's xmlrpc client library and represents a significant denial of service weakness that can be exploited remotely. This flaw specifically targets the gzip_decode function which processes compressed data within HTTP responses. The vulnerability affects Python versions 3.4 and earlier, making it a critical concern for systems running these outdated versions. The issue manifests when the xmlrpc client receives a specially crafted HTTP request containing malformed gzip compressed data, allowing attackers to trigger excessive memory consumption patterns that can ultimately lead to system resource exhaustion.
The technical implementation of this vulnerability stems from inadequate input validation within the gzip decompression logic of the xmlrpc client component. When the gzip_decode function processes maliciously constructed compressed data, it fails to properly handle boundary conditions and compression parameters that would normally be rejected by standard decompression routines. This weakness creates a scenario where the decompression process consumes exponentially increasing amounts of memory as it attempts to parse malformed compressed data structures. The flaw operates at the protocol level where HTTP responses containing crafted gzip content are processed without sufficient safeguards against malformed compression streams, leading to unbounded memory allocation patterns that can overwhelm system resources.
From an operational impact perspective, this vulnerability enables remote attackers to perform denial of service attacks against systems running vulnerable Python versions. The memory consumption pattern can be sustained over time, potentially causing system instability, application crashes, or complete system shutdowns depending on available memory resources. The attack vector requires only that an attacker can influence HTTP traffic to a system running the vulnerable xmlrpc client, making it particularly dangerous in networked environments where xmlrpc services might be exposed to untrusted networks. The vulnerability can be exploited through various means including web applications that utilize xmlrpc functionality, potentially affecting a wide range of services from web servers to enterprise applications that rely on Python's xmlrpc client libraries for inter-process communication.
The vulnerability aligns with CWE-400 which categorizes improper handling of resource identifiers and memory management issues in software systems. It also relates to ATT&CK technique T1499.004 which covers network denial of service attacks through resource exhaustion. Organizations should immediately upgrade to Python 3.5 or later versions where this vulnerability has been addressed through improved input validation and memory management in the xmlrpc client library. Additional mitigations include implementing network firewalls to restrict access to xmlrpc endpoints, configuring rate limiting on HTTP traffic, and monitoring for unusual memory consumption patterns that might indicate exploitation attempts. Security teams should also consider implementing intrusion detection systems that can identify malformed gzip content patterns in HTTP traffic and establish proper access controls to limit exposure of xmlrpc services to untrusted networks.