The Patching Friars' AlmanacA calendar of CVE saints

May 12

PrintDemonHoly card for printdemon, generated with AI (Claude, Anthropic) for the Lunario dei Frati Patchatori.CC BY-NC-SA 4.0 C:\Windows\ System32\… PrintDemon IMPRIMO ERGO SUM
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⚔ Commemorated today: The Great Plague of WannaCry (2017)☀ Commemorated today: The Miracle of MalwareTech's Domain (2017)

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Saint PrintDemon, Demon of the Spooler

Patron of the print spooler, printer ports that point to a file, and bugs surviving since Windows NT.

Life

On 12 May 2020, patch day, Yarden Shafir and Alex Ionescu described PrintDemon (CVE-2020-1048). Any user could create a printer whose port was a file on disk, and the spooler, running as SYSTEM, would "print" any content there, even after a reboot, because queued jobs resumed on their own. A year later the same service would give birth to PrintNightmare.

Prayer

O Saint PrintDemon, who prints where you should not, let our printers write only on paper. Amen.

How to celebrate

Celebrated by installing the May 2020 updates and disabling the spooler wherever nobody prints.

The spooler never sleeps, and neither do its demons.

Technical record

Disclosed on
May 12 2020
CVE
CVE-2020-1048
CVSS
7.8
Product
Microsoft · Windows 10 Version 1507

An elevation of privilege vulnerability exists when the Windows Print Spooler service improperly allows arbitrary writing to the file system. An attacker who successfully exploited this vulnerability could run arbitrary code with elevated system privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. To exploit this vulnerability, an attacker would have to log on to an affected system and run a specially crafted script or application. The update addresses the vulnerability by correcting how the Windows Print Spooler Component writes to the file system.

Sources: windows-internals.com

Commemorated today

Canonized by Pope Zerologon I

Related saints

Same product: Windows

Same year: 2020

Also remembered today

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