SRC-2021-0011 : Microsoft Exchange Server ImportTransportRuleCollection ProcessE15Format Remote Code Execution Vulnerability (patch bypass)

2020-12-0900:00:00

Steven Seeley (mr_me) of Qihoo 360 Vulcan Team

srcincite.io

6.6 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

HIGH

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/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

0.01 Low

EPSS

Percentile

83.3%

JSON

Vulnerability Details:

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

The specific flaw exists within the processing of the Import-TransportRuleCollection cmdlet. The issue results from the lack of proper validation of a user-supplied rule collection. 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-2021-26854>