CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
49.7%
Windows Kernel Elevation of Privilege Vulnerability
Recent assessments:
gwillcox-r7 at July 14, 2021 5:35pm UTC reported:
Update: Looks like this was used by the exploit brokerage company Candiru along with CVE-2021-33771 to deliver spyware to targeted users, which according to Microsoft’s blog post, affected at least 100 victims in Palestine, Israel, Iran, Lebanon, Yemen, Spain, United Kingdom, Turkey, Armenia, and Singapore. Victims include human rights defenders, dissidents, journalists, activists, and politicians.
Hmm, this is a particularly juicy bug as it seems to affect all Windows systems from Windows 7 up to the latest Windows 10. This is in contrast to CVE-2021-33771, which only affects Windows 8.1 and later. Both bugs affect the Windows Kernel and are being actively exploited in the wild for LPE.
There is little information on what actually is the issue here, although <https://twitter.com/mavillon1/status/1415149124064878593/> suggests that MiFlashDataSecton
, EtwpUpdatePeriodicCaptureState
and AlpcpProcessSynchronousRequest
may be possible culprits and reviewing AlpcpProcessSynchronousRequest
shows that a potential integer overflow was fixed.
Given that Microsoft also lists the attack complexity for both vulnerabilities as Low
it seems likely that other researchers will find a way to replicate these vulnerabilities and create working PoCs for them, particularly given that they have been exploited in the wild. Based on this evidence, it is highly recommended to patch these issues as soon as possible.
Further updates will be made to this post if and when these CVEs are tied to specific vulnerable functions.
Assessed Attacker Value: 4
Assessed Attacker Value: 4Assessed Attacker Value: 3
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
49.7%