CWE-85 双字符XSS操纵
Doubled Character XSS Manipulations
结构: Simple
Abstraction: Variant
状态: Draft
被利用可能性: unkown
基本描述
The web application does not filter user-controlled input for executable script disguised using doubling of the involved characters.
相关缺陷
-
cwe_Nature: ChildOf cwe_CWE_ID: 79 cwe_View_ID: 1000 cwe_Ordinal: Primary
-
cwe_Nature: ChildOf cwe_CWE_ID: 79 cwe_View_ID: 699 cwe_Ordinal: Primary
-
cwe_Nature: PeerOf cwe_CWE_ID: 675 cwe_View_ID: 1000
适用平台
Language: {'cwe_Class': 'Language-Independent', 'cwe_Prevalence': 'Undetermined'}
常见的影响
| 范围 | 影响 | 注释 |
|---|---|---|
| ['Confidentiality', 'Integrity', 'Availability'] | ['Read Application Data', 'Execute Unauthorized Code or Commands'] |
可能的缓解方案
Implementation
策略:
Resolve all filtered input to absolute or canonical representations before processing.
Implementation
策略:
Carefully check each input parameter against a rigorous positive specification (whitelist) defining the specific characters and format allowed. All input should be neutralized, not just parameters that the user is supposed to specify, but all data in the request, including tag attributes, hidden fields, cookies, headers, the URL itself, and so forth. A common mistake that leads to continuing XSS vulnerabilities is to validate only fields that are expected to be redisplayed by the site. We often encounter data from the request that is reflected by the application server or the application that the development team did not anticipate. Also, a field that is not currently reflected may be used by a future developer. Therefore, validating ALL parts of the HTTP request is recommended.
MIT-30.1 Implementation
策略: Output Encoding
Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component. The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.
MIT-43 Implementation
策略:
With Struts, write all data from form beans with the bean's filter attribute set to true.
MIT-31 Implementation
策略: Attack Surface Reduction
To help mitigate XSS attacks against the user's session cookie, set the session cookie to be HttpOnly. In browsers that support the HttpOnly feature (such as more recent versions of Internet Explorer and Firefox), this attribute can prevent the user's session cookie from being accessible to malicious client-side scripts that use document.cookie. This is not a complete solution, since HttpOnly is not supported by all browsers. More importantly, XMLHTTPRequest and other powerful browser technologies provide read access to HTTP headers, including the Set-Cookie header in which the HttpOnly flag is set.
分析过的案例
| 标识 | 说明 | 链接 |
|---|---|---|
| CVE-2002-2086 | XSS using "<script". | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-2086 |
| CVE-2000-0116 | Encoded "javascript" in IMG tag. | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2000-0116 |
| CVE-2001-1157 | Extra "<" in front of SCRIPT tag. | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2001-1157 |
分类映射
| 映射的分类名 | ImNode ID | Fit | Mapped Node Name |
|---|---|---|---|
| PLOVER | DOUBLE - Doubled character XSS manipulations, e.g. "<script" | ||
| Software Fault Patterns | SFP24 | Tainted input to command |
相关攻击模式
- CAPEC-245