CWE-203: Observable Discrepancy

Base Incomplete Simple

CWE版本: 4.18

更新日期: 2025-09-09

弱点描述

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not.

扩展描述

Discrepancies can take many forms, and variations may be detectable in timing, control flow, communications such as replies or requests, or general behavior. These discrepancies can reveal information about the product's operation or internal state to an unauthorized actor. In some cases, discrepancies can be used by attackers to form a side channel.

常见后果

影响范围: Confidentiality Access Control

技术影响: Read Application Data Bypass Protection Mechanism

说明: An attacker can gain access to sensitive information about the system, including authentication information that may allow an attacker to gain access to the system.

影响范围: Confidentiality

技术影响: Read Application Data

说明: When cryptographic primitives are vulnerable to side-channel-attacks, this could be used to reveal unencrypted plaintext in the worst case.

潜在缓解措施

阶段: Architecture and Design

策略: Separation of Privilege

阶段: Implementation

观察示例

参考: CVE-2020-8695

Observable discrepancy in the RAPL interface for some Intel processors allows information disclosure.

参考: CVE-2019-14353

Crypto hardware wallet's power consumption relates to total number of pixels illuminated, creating a side channel in the USB connection that allows attackers to determine secrets displayed such as PIN numbers and passwords

参考: CVE-2019-10071

Java-oriented framework compares HMAC signatures using String.equals() instead of a constant-time algorithm, causing timing discrepancies

参考: CVE-2002-2094

This, and others, use ".." attacks and monitor error responses, so there is overlap with directory traversal.

参考: CVE-2001-1483

Enumeration of valid usernames based on inconsistent responses

参考: CVE-2001-1528

Account number enumeration via inconsistent responses.

参考: CVE-2004-2150

User enumeration via discrepancies in error messages.

参考: CVE-2005-1650

User enumeration via discrepancies in error messages.

参考: CVE-2004-0294

Bulletin Board displays different error messages when a user exists or not, which makes it easier for remote attackers to identify valid users and conduct a brute force password guessing attack.

参考: CVE-2004-0243

Operating System, when direct remote login is disabled, displays a different message if the password is correct, which allows remote attackers to guess the password via brute force methods.

参考: CVE-2002-0514

Product allows remote attackers to determine if a port is being filtered because the response packet TTL is different than the default TTL.

参考: CVE-2002-0515

Product sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.

参考: CVE-2002-0208

Product modifies TCP/IP stack and ICMP error messages in unusual ways that show the product is in use.

参考: CVE-2004-2252

Behavioral infoleak by responding to SYN-FIN packets.

参考: CVE-2001-1387

Product may generate different responses than specified by the administrator, possibly leading to an information leak.

参考: CVE-2004-0778

Version control system allows remote attackers to determine the existence of arbitrary files and directories via the -X command for an alternate history file, which causes different error messages to be returned.

参考: CVE-2004-1428

FTP server generates an error message if the user name does not exist instead of prompting for a password, which allows remote attackers to determine valid usernames.

参考: CVE-2003-0078

SSL implementation does not perform a MAC computation if an incorrect block cipher padding is used, which causes an information leak (timing discrepancy) that may make it easier to launch cryptographic attacks that rely on distinguishing between padding and MAC verification errors, possibly leading to extraction of the original plaintext, aka the "Vaudenay timing attack."

参考: CVE-2000-1117

Virtual machine allows malicious web site operators to determine the existence of files on the client by measuring delays in the execution of the getSystemResource method.

参考: CVE-2003-0637

Product uses a shorter timeout for a non-existent user than a valid user, which makes it easier for remote attackers to guess usernames and conduct brute force password guessing.

参考: CVE-2003-0190

Product immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.

参考: CVE-2004-1602

FTP server responds in a different amount of time when a given username exists, which allows remote attackers to identify valid usernames by timing the server response.

参考: CVE-2005-0918

Browser allows remote attackers to determine the existence of arbitrary files by setting the src property to the target filename and using Javascript to determine if the web page immediately stops loading, which indicates whether the file exists or not.

引入模式

阶段 说明
Architecture and Design -
Implementation -

适用平台

编程语言
Not Language-Specific (Undetermined)
技术
Not Technology-Specific (Undetermined)

分类映射

分类名称 条目ID 条目名称 映射适配度
PLOVER - Discrepancy Information Leaks -
OWASP Top Ten 2007 A6 Information Leakage and Improper Error Handling CWE More Specific
OWASP Top Ten 2004 A7 Improper Error Handling CWE More Specific
关键信息

CWE ID: CWE-203

抽象级别: Base

结构: Simple

状态: Incomplete

相关弱点
相关攻击模式
CAPEC-189