CVE-2011-4610 in JBoss
Summary
by MITRE
JBoss Web, as used in Red Hat JBoss Communications Platform before 5.1.3, Enterprise Web Platform before 5.1.2, Enterprise Application Platform before 5.1.2, and other products, allows remote attackers to cause a denial of service (infinite loop) via vectors related to a crafted UTF-8 and a "surrogate pair character" that is "at the boundary of an internal buffer."
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Analysis
by VulDB Data Team • 04/24/2018
The vulnerability described in CVE-2011-4610 represents a critical denial of service flaw affecting JBoss Web components within various Red Hat JBoss product lines. This issue specifically targets the handling of UTF-8 encoded data streams and exploits a particular edge case involving surrogate pair characters that occur at buffer boundaries. The vulnerability exists in the core text processing mechanisms of these web application servers, where improper validation of UTF-8 sequences leads to catastrophic behavior rather than graceful error handling.
The technical root cause of this vulnerability lies in the improper implementation of UTF-8 decoding routines within JBoss Web's internal buffer management system. When a specially crafted UTF-8 sequence containing a surrogate pair character is processed, and this character恰好 falls exactly at the boundary of an internal processing buffer, the parsing logic enters an infinite loop. This occurs because the buffer boundary condition triggers a recursive or iterative processing pattern that fails to advance the parsing pointer properly, resulting in a state where the same invalid sequence is repeatedly processed without termination. The flaw operates at the level of character encoding validation and buffer management, making it particularly insidious as it can be triggered through normal HTTP request processing without requiring special privileges or authentication.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire application server operations. An attacker can craft malicious HTTP requests containing the specific UTF-8 surrogate pair pattern that triggers the infinite loop, causing the affected JBoss Web component to consume excessive CPU resources and effectively become unresponsive. This denial of service condition can persist for extended periods, potentially leading to complete application server shutdown or resource exhaustion that affects all services hosted on the vulnerable platform. The vulnerability affects multiple versions of Red Hat JBoss products, indicating a widespread exposure across various enterprise application server deployments.
Security practitioners should consider this vulnerability in the context of CWE-129, which addresses improper validation of buffer boundaries, and CWE-691, which covers insufficient control flow management in input processing. The ATT&CK framework categorizes this as a Denial of Service attack technique under the T1499.004 sub-technique for Network Denial of Service, where attackers exploit implementation flaws to exhaust system resources. Mitigation strategies should focus on immediate patch deployment for all affected JBoss versions, implementing input validation at the network level to detect and block malformed UTF-8 sequences, and establishing monitoring systems to detect unusual CPU consumption patterns that may indicate exploitation attempts. Organizations should also consider implementing rate limiting and connection throttling mechanisms as additional defensive measures to limit the impact of potential exploitation attempts.