CVE-2001-1243
MediumPublic exploitScripting.FileSystemObject in asp.dll for Microsoft IIS 4.0 and 5.0 allows local or remote attackers to cause a denial of service (crash) via (1) creating an ASP program that uses Scripting.FileSystemObject to open a file with an MS-DOS device name, or (2) remotely injecting the…
Published Jul 4, 2001 · Updated Apr 15, 2026
Key Facts
Patch immediately- CVE-2001-1243 is a medium-severity vulnerability (CVSS 5.0 v2) affecting Internet Information Server (Microsoft), Internet Information Services (Microsoft).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 71% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v2
5.0
AV:N/AC:L/Au:N/C:N/I:N/A:P
EPSS (30-day exploit likelihood)
71%
Higher than 99.3% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2001-1243 brief as a PDF
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Description
Scripting.FileSystemObject in asp.dll for Microsoft IIS 4.0 and 5.0 allows local or remote attackers to cause a denial of service (crash) via (1) creating an ASP program that uses Scripting.FileSystemObject to open a file with an MS-DOS device name, or (2) remotely injecting the device name into ASP programs that internally use Scripting.FileSystemObject.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Internet Information ServerMicrosoft | 4.0 | n/a |
| Internet Information ServicesMicrosoft | 5.0 | n/a |
Timeline
Publicly disclosed
Jul 4, 2001
Last updated
Apr 15, 2026
References
- advisoryiis-device-asp-dos(6800)
- patch2973
- exploitExploitDB-20989
- exploitExploitDB-20991
- other20010704 NERF Advisory #4: MS IIS local and remote DoS
FAQ
Common Questions.
Scripting.FileSystemObject in asp.dll for Microsoft IIS 4.0 and 5.0 allows local or remote attackers to cause a denial of service (crash) via (1) creating an ASP program that uses Scripting.FileSystemObject to open a file with an MS-DOS device name, or (2) remotely injecting the device name into ASP programs that inte…
Affected: Internet Information Server (Microsoft) versions 4.0; Internet Information Services (Microsoft) versions 5.0. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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