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Sid 1-1809


SERVER-APACHE Apache Chunked-Encoding worm attempt


Buffer overflow in the ism.dll ISAPI extension that implements HTR scripting in Internet Information Server (IIS) 4.0 and 5.0 allows attackers to cause a denial of service or execute arbitrary code via HTR requests with long variable names.


CVSS base score 7.5 CVSS impact score 6.4 CVSS exploitability score 10.0 confidentialityImpact PARTIAL integrityImpact PARTIAL availabilityImpact PARTIAL

Detailed information

Affected systems

  • microsoft internetinformationserver 4.0
  • microsoft internetinformationserver 5.0

Ease of attack

False positives

None known

False negatives

None known

Corrective action

Upgrade to the latest non-affected version of the software.

Apply the appropriate vendor supplied patches.


  • Talos research team.
  • This document was generated from data supplied by the national vulnerability database, a product of the national institute of standards and technology.
  • For more information see nvd.

Additional References