Used in attacks· fix by 2022-05-03Not scored yet

Microsoft Internet Information Services (IIS)

CVE-2017-7269

Microsoft Windows Server 2003 R2 contains a buffer overflow vulnerability in Internet Information Services (IIS) 6.0 which allows remote attackers to execute code via a long header beginning with "If: <http://" in a PROPFIND request.

What this means for your business

  • It affects Microsoft Internet Information Services (IIS). It matters if your company, or a supplier that handles your data, runs it.
  • Attackers are already using it. CISA added it to its list of flaws used in real attacks on 3 November 2021.
  • FIRST's prediction model gives it a 100% chance of attack attempts being seen in the next 30 days, ranking above 99% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run Microsoft Internet Information Services (IIS).
  2. 2If you do, follow CISA's required action below. No patch reference has been published yet.
  3. 3Treat it as urgent. US federal agencies must fix it by 3 May 2022. That deadline does not apply to private companies, but it shows how seriously CISA takes it.
  4. 4Because attackers have used it, check the affected systems for signs of a break-in, not only for the update.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Required action

Apply updates per vendor instructions.

CISA’s wording, unedited.

Scoring

CVSS
Not yet scored

Dates

Published
2021-11-03
Added to KEV
2021-11-03
Remediation due
2022-05-03
Sources
CISA KEV