Known Exploited Vulnerability
9.8
CRITICAL
CVE-2021-34523
Microsoft Exchange Server Privilege Escalation Vul - [Actively Exploited]
Description

Microsoft Exchange Server Elevation of Privilege Vulnerability

INFO

Published Date :

July 14, 2021, 6:15 p.m.

Last Modified :

Nov. 21, 2024, 6:10 a.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

5.9

Exploitability Score :

3.9
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

Description :

Microsoft Exchange Server contains an unspecified vulnerability that allows for privilege escalation.

Required Action :

Apply updates per vendor instructions.

Notes :

https://nvd.nist.gov/vuln/detail/CVE-2021-34523

Public PoC/Exploit Available at Github

CVE-2021-34523 has a 33 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2021-34523 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Microsoft exchange_server
: Total Affected Vendor : 1 | Products : 1
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-34523.

URL Resource
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html Exploit Third Party Advisory VDB Entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34523 Patch Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-822/ Third Party Advisory VDB Entry
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html Exploit Third Party Advisory VDB Entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34523 Patch Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-822/ Third Party Advisory VDB Entry

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
Ly4j/Exchange-ProxyShell-exp

Exchange ProxyShell exploit tool

Python

Updated: 1 month, 3 weeks ago
0 stars 0 fork 0 watcher
Born at : Dec. 27, 2024, 8:52 a.m. This repo has been linked 3 different CVEs too.
Profile Photo
pwnlog/ALinks

Collection of links for AD purple teamers.

Updated: 2 months, 4 weeks ago
0 stars 0 fork 0 watcher
Born at : Feb. 17, 2024, 2:49 p.m. This repo has been linked 16 different CVEs too.
Profile Photo
nitish778191/fitness_app

None

Updated: 6 months, 2 weeks ago
0 stars 0 fork 0 watcher
Born at : Sept. 4, 2023, 6:14 a.m. This repo has been linked 25 different CVEs too.
Profile Photo
SUPRAAA-1337/CVE-2021-34523

test-yaml

Updated: 11 months ago
2 stars 0 fork 0 watcher
Born at : Sept. 2, 2023, 12:26 p.m. This repo has been linked 1 different CVEs too.
Profile Photo
CVEDB/awesome-cve-repo

None

Shell

Updated: 2 weeks, 3 days ago
4 stars 2 fork 2 watcher
Born at : March 23, 2023, 4:32 a.m. This repo has been linked 265 different CVEs too.
Profile Photo
CVEDB/top

None

Shell

Updated: 2 weeks, 3 days ago
1 stars 0 fork 0 watcher
Born at : March 19, 2023, 1:53 a.m. This repo has been linked 265 different CVEs too.
Profile Photo
laoqin1234/https-github.com-HackingCost-AD_Pentest

None

Updated: 1 year, 10 months ago
1 stars 2 fork 2 watcher
Born at : Nov. 20, 2022, 3:38 a.m. This repo has been linked 18 different CVEs too.
Profile Photo
weeka10/-hktalent-TOP

None

Shell

Updated: 1 year, 11 months ago
2 stars 0 fork 0 watcher
Born at : Nov. 16, 2022, 9:38 a.m. This repo has been linked 256 different CVEs too.
Profile Photo
HackingCost/AD_Pentest

红队|域渗透重要漏洞汇总(持续更新)

Updated: 3 weeks, 4 days ago
274 stars 37 fork 37 watcher
Born at : Nov. 15, 2022, 2:23 a.m. This repo has been linked 20 different CVEs too.
Profile Photo
cyberanand1337x/bug-bounty-2022

None

Updated: 2 years, 1 month ago
0 stars 0 fork 0 watcher
Born at : Sept. 30, 2022, 6:29 p.m. This repo has been linked 253 different CVEs too.
Profile Photo
jbmihoub/all-poc

None

Shell

Updated: 6 months, 2 weeks ago
1 stars 2 fork 2 watcher
Born at : Aug. 25, 2022, 12:16 a.m. This repo has been linked 250 different CVEs too.
Profile Photo
Astrogeorgeonethree/Starred2

A curated list of my GitHub Stars

Updated: 8 months ago
1 stars 1 fork 1 watcher
Born at : July 5, 2022, 7:40 p.m. This repo has been linked 32 different CVEs too.
Profile Photo
kh4sh3i/ProxyShell

CVE-2021-34473 Microsoft Exchange Server Remote Code Execution Vulnerability

Python

Updated: 2 weeks, 5 days ago
36 stars 6 fork 6 watcher
Born at : June 29, 2022, 12:37 p.m. This repo has been linked 4 different CVEs too.
Profile Photo
merlinepedra/RedTeam_toolkit

None

Dockerfile Python Shell CSS JavaScript HTML

Updated: 2 years, 7 months ago
2 stars 0 fork 0 watcher
Born at : June 26, 2022, 2:40 a.m. This repo has been linked 5 different CVEs too.
Profile Photo
merlinepedra25/RedTeam_toolkit

None

Dockerfile Python Shell CSS JavaScript HTML

Updated: 6 months, 1 week ago
1 stars 0 fork 0 watcher
Born at : June 26, 2022, 2:40 a.m. This repo has been linked 5 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-34523 vulnerability anywhere in the article.

  • TheCyberThrone
Ghost Ransomware Dissection

Ghost Ransomware, also known by various aliases such as Cring, Crypt3r, Phantom, Strike, Hello, Wickrme, HsHarada, and Rapture, is a sophisticated ransomware threat that has targeted organizations glo ... Read more

Published Date: Feb 20, 2025 (2 days, 2 hours ago)
CVE-2025-1094 CVE-2021-34523 CVE-2021-34473 CVE-2021-31207 CVE-2018-13379 CVE-2010-2861 CVE-2009-3960
  • security.nl
FBI meldt ransomware-aanvallen via 15 jaar oude Adobe-kwetsbaarheden

De FBI en het Amerikaanse cyberagentschap CISA waarschuwen voor aanvallen met de Ghost-ransomware, waarbij onder andere gebruik wordt gemaakt van Adobe-kwetsbaarheden waarvoor in 2010 beveiligingsupda ... Read more

Published Date: Feb 20, 2025 (2 days, 5 hours ago)
CVE-2021-34523 CVE-2021-34473 CVE-2021-31207 CVE-2018-13379 CVE-2019-0604 CVE-2010-2861 CVE-2009-3960
  • The Register
Ghost ransomware crew continues to haunt IT depts with scarily bad infosec

The operators of Ghost ransomware continue to claim victims and score payments, but keeping the crooks at bay is possible by patching known vulnerabilities and some basic infosec actions, according to ... Read more

Published Date: Feb 20, 2025 (2 days, 5 hours ago)
CVE-2021-34523 CVE-2021-34473 CVE-2021-31207 CVE-2018-13379 CVE-2019-0604 CVE-2010-2861 CVE-2009-3960
  • Cyber Security News
Ghost Ransomware Compromised Organisations Across 70+ Countries – CISA & FBI Warns

The Federal Bureau of Investigation (FBI) and Cybersecurity and Infrastructure Security Agency (CISA) have issued a joint advisory warning of widespread attacks by the Ghost ransomware group, which ha ... Read more

Published Date: Feb 20, 2025 (2 days, 6 hours ago)
CVE-2021-34523 CVE-2021-34473 CVE-2021-31207 CVE-2018-13379 CVE-2017-0143 CVE-2010-2861 CVE-2009-3960
  • The Cyber Express
Ghost Ransomware Group Exploiting Unpatched Software, FBI and CISA Warn

A Ghost ransomware group also referred to as Cring, has been actively exploiting vulnerabilities in software and firmware as recently as January 2025, according to an alert issued Wednesday by the Fed ... Read more

Published Date: Feb 20, 2025 (2 days, 7 hours ago)
CVE-2025-0994 CVE-2021-34523 CVE-2021-34473 CVE-2021-31207 CVE-2018-13379 CVE-2019-0604 CVE-2010-2861 CVE-2009-3960
  • BleepingComputer
CISA and FBI: Ghost ransomware breached orgs in 70 countries

CISA and the FBI said attackers deploying Ghost ransomware have breached victims from multiple industry sectors across over 70 countries, including critical infrastructure organizations. Other industr ... Read more

Published Date: Feb 19, 2025 (2 days, 17 hours ago)
CVE-2021-34523 CVE-2021-34473 CVE-2021-31207 CVE-2018-13379 CVE-2010-2861 CVE-2009-3960
  • BleepingComputer
CISA says BianLian ransomware now focuses only on data theft

The BianLian ransomware operation has shifted its tactics, becoming primarily a data theft extortion group, according to an updated advisory from the U.S. Cybersecurity & Infrastructure Security Agenc ... Read more

Published Date: Nov 21, 2024 (3 months ago)
CVE-2022-37969 CVE-2021-34523 CVE-2021-34473 CVE-2021-31207
  • AttackIQ
Response to CISA Advisory (AA24-317A): 2023 Top Routinely Exploited Vulnerabilities

On November 12, 2024, the U.S. Cybersecurity & Infrastructure Security Agency (CISA) released a Cybersecurity Advisory (CSA) providing details on the Common Vulnerabilities and Exposures (CVEs) routin ... Read more

Published Date: Nov 13, 2024 (3 months, 1 week ago)
CVE-2023-4966 CVE-2023-34362 CVE-2023-27350 CVE-2022-47966 CVE-2022-42475 CVE-2022-26134 CVE-2021-4034 CVE-2021-44228 CVE-2021-40539 CVE-2021-34523 ...+4 more CVE
  • The Hacker News
Chinese-Speaking Hacker Group Targets Human Rights Studies in Middle East

Unnamed government entities in the Middle East and Malaysia are the target of a persistent cyber campaign orchestrated by a threat actor known as Tropic Trooper since June 2023. "Sighting this group's ... Read more

Published Date: Sep 05, 2024 (5 months, 2 weeks ago)
CVE-2023-26360 CVE-2021-34523 CVE-2021-34473 CVE-2021-31207
  • Kaspersky
Tropic Trooper spies on government entities in the Middle East

Executive summary Tropic Trooper (also known as KeyBoy and Pirate Panda) is an APT group active since 2011. This group has traditionally targeted sectors such as government, healthcare, transportation ... Read more

Published Date: Sep 05, 2024 (5 months, 2 weeks ago)
CVE-2023-26360 CVE-2021-34523 CVE-2021-34473 CVE-2021-31207
  • Google Cloud
Ransomware Rebounds: Extortion Threat Surges in 2023, Attackers Rely on Publicly Available and Legitimate Tools

Written by: Bavi Sadayappan, Zach Riddle, Jordan Nuce, Joshua Shilko, Jeremy Kennelly A version of this blog post was published to the Mandiant Advantage portal on April 18, 2024. Executive Summary In ... Read more

Published Date: Jun 03, 2024 (8 months, 2 weeks ago)
CVE-2023-22518 CVE-2023-46604 CVE-2023-4966 CVE-2023-40044 CVE-2023-20269 CVE-2023-3519 CVE-2023-3539 CVE-2023-28252 CVE-2023-24880 CVE-2022-47966 ...+11 more CVE

The following table lists the changes that have been made to the CVE-2021-34523 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html
    Added Reference https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34523
    Added Reference https://www.zerodayinitiative.com/advisories/ZDI-21-822/
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Modified Analysis by [email protected]

    Feb. 13, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Dec. 28, 2023

    Action Type Old Value New Value
    Changed Description Microsoft Exchange Server Elevation of Privilege Vulnerability This CVE ID is unique from CVE-2021-33768, CVE-2021-34470. Microsoft Exchange Server Elevation of Privilege Vulnerability
    Added CVSS V3.1 Microsoft Corporation AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
  • CWE Remap by [email protected]

    Jul. 12, 2022

    Action Type Old Value New Value
    Changed CWE CWE-269 CWE-287
  • Modified Analysis by [email protected]

    Sep. 21, 2021

    Action Type Old Value New Value
    Changed Reference Type http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html No Types Assigned http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html Exploit, Third Party Advisory, VDB Entry
  • CVE Modified by [email protected]

    Aug. 20, 2021

    Action Type Old Value New Value
    Added Reference http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html [No Types Assigned]
  • Initial Analysis by [email protected]

    Jul. 22, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:P/A:P)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Changed Reference Type https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34523 No Types Assigned https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34523 Patch, Vendor Advisory
    Changed Reference Type https://www.zerodayinitiative.com/advisories/ZDI-21-822/ No Types Assigned https://www.zerodayinitiative.com/advisories/ZDI-21-822/ Third Party Advisory, VDB Entry
    Added CWE NIST CWE-269
    Added CPE Configuration OR *cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:* *cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:* *cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:* *cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:* *cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Jul. 19, 2021

    Action Type Old Value New Value
    Added Reference https://www.zerodayinitiative.com/advisories/ZDI-21-822/ [No Types Assigned]
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-34523 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-34523 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

95.88 }} 11.07%

score

0.99606

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: