Microsoft Windows Print Spooler Remote Code Execution Vulnerability

Windows Print Spooler Remote Code Execution Vulnerability

CheckOps priority index

8.1/10 Patch within 24 h

Severity7.8

Probability8.5

Exploitation4/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 85.3% higher than 99.7% of CVEs

CVSS 3.1 7.8 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:

Exploited for 1,826 days 03 Nov 2021

CISA due date 17 Nov 2021 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 4 / 5

KEV catalog (CISA)03 Nov 2021
Exploited in EUVD (ENISA)03 Nov 2021
Used by ransomwareyes
EPSS above 10 %85.3%
No account, over the networkno

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

Windows Server 2008 Service Pack 2 (Server Core installation)Windows 10 Version 1909Windows Server 2019Windows Server 2012 R2Windows 10 Version 2004Windows Server version 2004Windows 7Windows Server 2012 R2 (Server Core installation)Windows 10 Version 1809Windows Server 2008 Service Pack 2Windows Server 2012 (Server Core installation)Windows 10 Version 21H1Windows 10 Version 1607Windows Server 2016Windows 8.1Windows 7 Service Pack 1Windows 10 Version 20H2Windows Server 2012Windows Server 2008 R2 Service Pack 1 (Server Core installation)Windows Server 2008 R2 Service Pack 1Windows Server 2016 (Server Core installation)Windows Server 2008 Service Pack 2Windows Server 2019 (Server Core installation)Windows Server version 20H2Windows 10 Version 1507Windows

Affected versions

6.0.0 <6.0.6003.21137
10.0.0 <10.0.18363.1621
10.0.0 <10.0.17763.1999
6.3.0 <6.3.9600.20045
10.0.0 <10.0.19041.1052
6.1.0 <6.1.7601.25632
6.3.0 <6.3.9600.20044
6.2.0 <6.2.9200.23372
10.0.0 <10.0.19043.1052
10.0.0 <10.0.14393.4467
10.0.0 <10.0.19042.1052
6.0.0 <6.1.7601.25632

Weaknesses (CWE)

CWE-285

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

08 Jun 2021
Published
03 Nov 2021
Exploitation reported (ENISA)
03 Nov 2021
Added to the KEV catalog
17 Nov 2021
CISA remediation due date
26 Sept 2026
EPSS peak: 85.3%

References

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