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srcinciteSteven Seeley (mr_me) of Qihoo 360 Vulcan TeamSRC-2021-0013
HistoryDec 09, 2020 - 12:00 a.m.

SRC-2021-0013 : Microsoft Exchange Server DlpUtils AddTenantDlpPolicy ruleParameters TOCTOU Remote Code Execution Vulnerability (patch bypass)

2020-12-0900:00:00
Steven Seeley (mr_me) of Qihoo 360 Vulcan Team
srcincite.io
41

9.1 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

HIGH

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

6.5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

SINGLE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:L/Au:S/C:P/I:P/A:P

0.036 Low

EPSS

Percentile

91.4%

Vulnerability Details:

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exchange Server. Authentication with the “Data Loss Prevention” role is required to exploit this vulnerability.

The specific flaw exists within the processing of the New-DlpPolicy cmdlet. The issue results from the lack of proper validation of user-supplied ruleParameters when creating a dlp policy. An attacker can leverage this vulnerability to execute code in the context of SYSTEM.

Affected Vendors:

Microsoft

Affected Products:

Exchange Server

Vendor Response:

Microsoft has issued an update to correct this vulnerability. More details can be found at: <https://portal.msrc.microsoft.com/security-guidance/advisory/CVE-2021-26412&gt;

9.1 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

HIGH

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

6.5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

SINGLE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:L/Au:S/C:P/I:P/A:P

0.036 Low

EPSS

Percentile

91.4%