CVE-2004-0847
published 2004-11-03CVE-2004-0847: The Microsoft .NET forms authentication capability for ASP.NET allows remote attackers to bypass authentication for .aspx files in restricted directories via a…
PriorityP276critical9.8CVSS 3.0
AVNACLPRNUINSUCHIHAH
ITWEXPLOITVulnCheck KEV
Exploited in the wild
EPSS
75.70%
99.5th percentile
The Microsoft .NET forms authentication capability for ASP.NET allows remote attackers to bypass authentication for .aspx files in restricted directories via a request containing a (1) "\" (backslash) or (2) "%5C" (encoded backslash), aka "Path Validation Vulnerability."
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | asp.net | <= 1.1 | — |
| microsoft | asp.net | — | — |
Detection & IOCsextracted from sources · hover to see the quote
- →Detect requests to .aspx files in restricted/secured directories containing a literal backslash '\' in the URI path, which bypasses ASP.NET Forms Authentication. ↗
- →Detect requests to .aspx files in restricted/secured directories containing the URL-encoded backslash '%5C' in the URI path, which bypasses ASP.NET Forms Authentication. ↗
- →Monitor for URI patterns matching '<secureDirectory>\<filename>.aspx' or '<secureDirectory>%5C<filename>.aspx' in web server access logs targeting ASP.NET 1.x applications. ↗
- ·The bypass specifically targets the Microsoft .NET Forms Authentication capability for ASP.NET; only .aspx files in directories protected by Forms Authentication are affected. ↗
- ·The two attack vectors behave differently across browsers: the literal backslash '\' variant is effective via Mozilla-based browsers, while the '%5C' encoded variant is effective via Microsoft Internet Explorer. ↗
CVSS provenance
nvdv3.09.8CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
vulncheck9.8CRITICAL
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GHSA
GHSA-wxfc-g96x-mm56: The Microsoft
ghsa_unreviewed·2022-04-29
CVE-2004-0847 [CRITICAL] CWE-22 GHSA-wxfc-g96x-mm56: The Microsoft
The Microsoft .NET forms authentication capability for ASP.NET allows remote attackers to bypass authentication for .aspx files in restricted directories via a request containing a (1) "\" (backslash) or (2) "%5C" (encoded backslash), aka "Path Validation Vulnerability."
VulnCheck
Microsoft asp.net Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
vulncheck·2004·CVSS 9.8
CVE-2004-0847 [CRITICAL] Microsoft asp.net Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Microsoft asp.net Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The Microsoft .NET forms authentication capability for ASP.NET allows remote attackers to bypass authentication for .aspx files in restricted directories via a request containing a (1) "\" (backslash) or (2) "%5C" (encoded backslash), aka "Path Validation Vulnerability."
Affected: Microsoft asp.net
Required Action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Exploitation References: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2005/ms05-004
No detection rules found.
No writeups or analysis indexed.
CWE
Path Equivalence: 'filedir\' (Trailing Backslash)
mitre_cwe·CVSS 7.5
[HIGH] CWE-54 Path Equivalence: 'filedir\' (Trailing Backslash)
CWE-54: Path Equivalence: 'filedir\' (Trailing Backslash)
The product accepts path input in the form of trailing backslash ('filedir\') without appropriate validation, which can lead to ambiguous path resolution and allow an attacker to traverse the file system to unintended locations or access arbitrary files.
Modes of Introduction:
Phase: Implementation
Phase: Porting
Common Consequences:
Scope: Confidentiality, Integrity. Impact: Read Files or Directories, Modify Files or Directories.
Potential Mitigations:
[Implementation] Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validati
CWE
Improper Handling of URL Encoding (Hex Encoding)
mitre_cwe·CVSS 7.5
[HIGH] CWE-177 Improper Handling of URL Encoding (Hex Encoding)
CWE-177: Improper Handling of URL Encoding (Hex Encoding)
The product does not properly handle when all or part of an input has been URL encoded.
Modes of Introduction:
Phase: Implementation
Common Consequences:
Scope: Integrity. Impact: Unexpected State.
Potential Mitigations:
[Architecture and Design] Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
[Implementation] Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including le
CWE
Improper Resolution of Path Equivalence
mitre_cwe
CWE-41 Improper Resolution of Path Equivalence
CWE-41: Improper Resolution of Path Equivalence
The product is vulnerable to file system contents disclosure through path equivalence. Path equivalence involves the use of special characters in file and directory names. The associated manipulations are intended to generate multiple names for the same object.
Path equivalence is usually employed in order to circumvent access controls expressed using an incomplete set of file name or file path representations. This is different from path traversal, wherein the manipulations are performed to generate a name for a different object.
Modes of Introduction:
Phase: Implementation
Common Consequences:
Scope: Confidentiality, Integrity, Access Control. Impact: Read Files or Directories, Modify Files or Directories, Bypass Protection Mechanism. A
CWE
Improper Neutralization of Trailing Special Elements
mitre_cwe
CWE-162 Improper Neutralization of Trailing Special Elements
CWE-162: Improper Neutralization of Trailing Special Elements
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes trailing special elements that could be interpreted in unexpected ways when they are sent to a downstream component.
As data is parsed, improperly handled trailing special elements may cause the process to take unexpected actions that result in an attack.
Modes of Introduction:
Phase: Implementation
Common Consequences:
Scope: Integrity. Impact: Unexpected State.
Potential Mitigations:
Developers should anticipate that trailing special elements will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appro
CWE
Authentication Bypass by Alternate Name
mitre_cwe
CWE-289 Authentication Bypass by Alternate Name
CWE-289: Authentication Bypass by Alternate Name
The product performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor.
Modes of Introduction:
Phase: Architecture and Design
Note: COMMISSION: This weakness refers to an incorrect design related to an architectural security tactic.
Phase: Implementation
Common Consequences:
Scope: Access Control. Impact: Bypass Protection Mechanism.
Detection Methods:
Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically,
http://archives.neohapsis.com/archives/ntbugtraq/2004-q3/0221.htmlhttp://sourceforge.net/mailarchive/forum.php?thread_id=5671607&forum_id=24754http://www.kb.cert.org/vuls/id/283646http://www.securityfocus.com/bid/11342http://www.us-cert.gov/cas/techalerts/TA05-039A.htmlhttps://docs.microsoft.com/en-us/security-updates/securitybulletins/2005/ms05-004https://exchange.xforce.ibmcloud.com/vulnerabilities/17644https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A3556https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A4987http://archives.neohapsis.com/archives/ntbugtraq/2004-q3/0221.htmlhttp://sourceforge.net/mailarchive/forum.php?thread_id=5671607&forum_id=24754http://www.kb.cert.org/vuls/id/283646http://www.securityfocus.com/bid/11342http://www.us-cert.gov/cas/techalerts/TA05-039A.htmlhttps://docs.microsoft.com/en-us/security-updates/securitybulletins/2005/ms05-004https://exchange.xforce.ibmcloud.com/vulnerabilities/17644https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A3556https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A4987
2004-11-03
Published
Exploited in the wild