Servers and applications
CVE-2009-4445
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…
- Severity
- Medium 6.0
- Published
- 29 Dec 2009
- Last changed
- 16 Jun 2026
- Added to UpHeron
- 21 Oct 2026
- Exploit chance
- 13% in the next 30 daysHigher than 96% of CVEs. EPSS by FIRST, 12 Nov 2026
- Attack
- Over the network · Needs a login
- Attacker can
- Read some data · Change some data · Slow it down
- CVSS vector
AV:N/AC:M/Au:S/C:P/I:P/A:P- Sources
- NVD
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 software
| Software | Affected versions |
|---|---|
Microsoft IISServers and applications · cpe:a:microsoft:internet_information_services |
|