Description
ISM.DLL in IIS 4.0 and 5.0 allows remote attackers to read file contents by requesting the file and appending a large number of encoded spaces (%20) and terminated with a .htr extension, aka the ".HTR File Fragment Reading" or "File Fragment Reading via .HTR" vulnerability.
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- Microsoft IIS 4.0/5.0 - Malformed Filename Request EDB-19908 · remote · May 11, 2000 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
References
- 20000511 Alert: IIS ism.dll exposes file contents mailing-list
- MS00-031 vendor-advisory
- iis-ism-file-access(4448) vdb-entry
- 1193 vdb-entry