What’s Vulnerable › Vulnerabilities

CVE-2009-4445

• Severity: medium (CVSS 6.0 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 12.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2009-12-29 · updated 2026-06-16
• Weakness: CWE-20

Description

Microsoft Internet Information Services (IIS), when used in conjunction with unspecified third-party upload applications, allows remote attackers to create empty files with arbitrary extensions via a filename containing an initial extension followed by a : (colon) and a safe extension, as demonstrated by an upload of a .asp:.jpg file that results in creation of an empty .asp file, related to support for the NTFS Alternate Data Streams (ADS) filename syntax. NOTE: it could be argued that this is a vulnerability in the third-party product, not IIS, because the third-party product should be applying its extension restrictions to the portion of the filename before the colon.

Affected products

• Microsoft IIS: through 6.0

References

• http://securitytracker.com/id?1023387
• http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf
• https://exchange.xforce.ibmcloud.com/vulnerabilities/55308
• http://securitytracker.com/id?1023387
• http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf
• https://exchange.xforce.ibmcloud.com/vulnerabilities/55308

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