PT-2021-3815 · Microsoft · Exchange Server

Orangetw · Published 2021-07-13 · Updated 2026-05-20 · CVE-2021-34473

Positive Technologies (AI Summary)

CVSS v2.0

10

Critical

Base vector

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

Name of the Vulnerable Software and Affected Versions Microsoft Exchange Server versions 2013 through 2019

Description The issue is related to errors in code generation management, allowing a remote attacker to execute arbitrary code. This can impact the system. The estimated number of potentially affected devices worldwide is not specified. There have been real-world incidents where this issue was exploited, including a critical MS Exchange ProxyShell attack.

Recommendations For Microsoft Exchange Server versions 2013 through 2019, update to a version that contains a fix for this issue. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

RCE

Code Injection

SSRF

Weakness Enumeration

CWE-94

CWE-918

Related Identifiers

BDU:2021-04125

CVE-2021-34473

ZDI-21-821

Affected Products

Exchange Server

References · 122

• 🔥 https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/http/exchange_proxyshell_rce.rb · Exploit
• 🔥 https://github.com/horizon3ai/proxyshell · Exploit
• 🔥 https://github.com/cyberheartmi9/Proxyshell-Scanner · Exploit
• 🔥 https://github.com/phamphuqui1998/CVE-2021-34473 · Exploit
• 🔥 https://github.com/p2-98/CVE-2021-34473 · Exploit
• 🔥 https://github.com/kh4sh3i/ProxyShell · Exploit
• 🔥 https://github.com/je6k/CVE-2021-34473-Exchange-ProxyShell · Exploit
• 🔥 https://github.com/RaouzRouik/CVE-2021-34473-scanner · Exploit
• 🔥 http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html · Exploit
• https://zerodayinitiative.com/advisories/ZDI-21-821 · Security Note
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34473 · Vendor Advisory
• https://bdu.fstec.ru/vul/2021-04125 · Security Note
• https://osv.dev/vulnerability/CVE-2021-34473 · Vendor Advisory
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-34473 · Security Note