7.5
CVSSv2

CVE-2021-26855

Published: 03/03/2021 Updated: 26/03/2021
CVSS v2 Base Score: 7.5 | Impact Score: 6.4 | Exploitability Score: 10
CVSS v3 Base Score: 9.8 | Impact Score: 5.9 | Exploitability Score: 3.9
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P

Vulnerability Summary

Microsoft Exchange Server could allow a remote malicious user to execute arbitrary code on the system. By sending a specially-crafted request, an attacker could exploit this vulnerability to execute arbitrary code on the system with privileges of the victim.

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This Metasploit module exploits a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authentication, impersonating as the admin (CVE-2021-26855) and write arbitrary file (CVE-2021-27065) to get the RCE (Remote Code Execution) By taking advantage of this vulnerability, you can execute arbitrary commands on the remote M ...

Github Repositories

ProxyLogon Pre-Auth SSRF To Arbitrary File Write For Education and Research Tested on: Windows - Python 3 /Linux - Python 3 If you are not script kiddies, you will know how to run proxylogon Sometime, some server extract domain tld is wrong Download userstxt list from github or u find it with Google Dork: intext:'@domainltd' Sorry my bad english Reference:

ProxyLogon ProxyLogon is the formally generic name for CVE-2021-26855, a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authentication and impersonating as the admin We have also chained this bug with another post-auth arbitrary-file-write vulnerability, CVE-2021-27065, to get code execution (source: proxylogoncom) Disclaimer The information

CVE-2021-26855-SSRF-Exchange CVE-2021-26855 SSRF Exchange Server Shodan betashodanio/search?query=httpcomponent%3A%22outlook+web+app%22 betashodanio/search?query=httphtml%3A%22%2Fowa%22 Fofa fofaso/result?q=title%3D%22Outlook+Web+App%22 fofaso/result?q=%22%2Fowa%22&qbase64=Ii9vd2Ei Zoomeye wwwzoomeyeorg/searchResult?

ProxyLogon-CVE-2021-26855 RCE exploit for ProxyLogon vulnerability in Microsoft Exchange Working with Python 39 Usage: python proxylogon_rcepy target email command Example: python proxylogon_rcepy 192168227137 administrator@testlocal whoami All credits go to DEVCORE, based on f5pm/go-62102html

CVE-2021-26855_Exchange RCE 本文以及工具仅限技术分享,严禁用于非法用途,否则产生的一切后果自行承担。 Microsoft Exchange Proxylogon Exploit Chain EXP分析 + CVE-2021–26855 + CVE-2021–27065 复现总结

CVE-2021-26855_SSRF CVE-2021-26855 Exchange SSRF POC change the ceyeio tokne & Identifier : token = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX' dns_url = randomstr + 'XXXXXXceyeio' python CVE-2021-26855_SSRFpy acom

CVE-2021-26855_PoC My early SSRF payloads (CVE-2021-26855) over Exchange Server 2019 Payload (1) # curl -i -s -k -X $'GET' -H $'Host: <exchange_server>' -H $'User-Agent: alex666' -H $'Connection: close' -b $'X-AnonResource=true; X-AnonResource-Backend=8r0apyvx5dt613lnaabo1qotwk2bq0burpcollaboratornet/ecp/defaultfl

CVE-2021-26855 PoC of proxylogon chain SSRF(CVE-2021-26855) to write file by testanull, censored by github Why does github remove this exploit because it is against the acceptable use policy - but tons of other proof of concept exploits and frameworks are OK? githubcom/rapid7/metasploit-framework Lots of CVE exploit repositories Is it because Github is owned by Micro

CVE-2021-26855 exploit-Exchange Auto Scan the World and auto exploit rce By EOG Team

ProxyLogon (CVE-2021-26855) CVE-2021-26855, also known as ProxyLogon, is a server-side request forgery (SSRF) vulnerability in Exchange that allows an attacker to send arbitrary HTTP requests and authenticate as the Exchange server According to Orange Tsai, the researcher who discovered the vulnerabilities, CVE-2021-26855 allows code execution when chained with CVE-2021-2706

ExchangeWeaknessTest This script test the CVE-2021-26855 vulnerability on Exchange Server Example python3 ExchangeWeaknessTestpy mydomaincom Licence Licensed under the GPL, version 3

CSIRT clean_up Low tech powershell script to clean up files and the registry based on input files Hafnium IOC's IOCs (IP addresses, hashes of web shell aspx files) used in exploiting CVE-2021-26855 courtesy of Volexity, Microsoft, Huntresslabs, PwnDefend and our own research

I have translated the chinese exploit at githubcom/jsdryan/CVE-2021-26855 for english reader and people unfamiliar with golang just look at the png pictures

CVE-2021-26855-Scanner Scanner and PoC for CVE-2021-26855 Credit to GreyOrder for the PoC Reuploading for convenience and because Microsoft took it down at least once :) Example of usage for mass scanning: shodan download --limit 12345 exchange "httpcomponent:'outlook web+app'" gzip -d exchangejsongz shodan parse exchangejson --fields=ip_str,port &g

ProxyLogon PoC of proxylogon chain SSRF(CVE-2021-26855) to write file testanull/PoC_proxyLogonpy webarchiveorg/web/20210310164403/gistgithubcom/testanull/fabd8eeb46f120c4b15f8793617ca7d1

Microsoft_Exchange_Server_SSRF_CVE-2021-26855 zoomeye dork:app:"Microsoft Exchange Server" 使用Seebug工具箱及pocsuite3编写的脚本Microsoft_Exchange_Server_SSRF_CVE-2021-26855py,对近一年的数据进行探测: 成功率约为:1500 / 5000 = 30%

ProxyLogon-CVE-2021-26855-metasploit CVE-2021-26855 proxyLogon exchange ssrf to arbitrary file write metasploit exploit script preparation git clone githubcom/TaroballzChen/ProxyLogon-CVE-2021-26855-metasploit cd ProxyLogon-CVE-2021-26855-metasploit mkdir -p ~/msf4/modules/exploits/windows/ cp exchange_ssrf_to_arbitrary_file_writepy ~/msf4/modules/exploits/windows/

CVE-2021-26855-Exchange-RCE Microsoft Exchange Proxylogon Exploit Chain EXP分析 + CVE-2021–26855 + CVE-2021–27065 复现总结

Exchange SSRF toRCE Exploit For educational and learning purposes only CVE-2021-26855 CVE-2021-27065 Usage [*] ProxyLogon-Exchange SSRF to RCE Exploit Chain - Author @Evilash /Exchange_SSRFtoRCEChainExploitpy <url> <MailUser> Real and stable exploit to RCE , enjoy it :) Fofa Quary microsoft exchange 2013: app="Microsoft-E

Ladon Scanner For Golang Wiki k8gegeorg/Ladon/LadonGohtml 简介 LadonGo一款开源内网渗透扫描器框架,使用它可轻松一键探测C段、B段、A段存活主机、指纹识别、端口扫描、密码爆破、远程执行、高危漏洞检测等。36版本包含28个模块功能,高危漏洞检测MS17010、SmbGhost,远程执行SshCmd、WinrmCmd、PhpS

CVE-2021-26855-SSRF-Exchange CVE-2021-26855 SSRF Exchange Server Shodan betashodanio/search?query=httpcomponent%3A%22outlook+web+app%22 betashodanio/search?query=httphtml%3A%22%2Fowa%22 Fofa fofaso/result?q=title%3D%22Outlook+Web+App%22 fofaso/result?q=%22%2Fowa%22&qbase64=Ii9vd2Ei Zoomeye wwwzoomeyeorg/searchResult?q=

CVE-2021-26855-SSRF-Exchange CVE-2021-26855 SSRF Exchange Server Shodan betashodanio/search?query=httpcomponent%3A%22outlook+web+app%22 betashodanio/search?query=httphtml%3A%22%2Fowa%22 Fofa fofaso/result?q=title%3D%22Outlook+Web+App%22 fofaso/result?q=%22%2Fowa%22&qbase64=Ii9vd2Ei Zoomeye wwwzoomeyeorg/searchResult?

CVE-2021-26855-SSRF-Poc This script helps to identify CVE-2021-26855 ssrf Poc Reference: proxylogoncom/ Script usage python CVE-2021-26855py -H targetcom -B xxxxxxxxxxxxxxxxxxburpcollaboratornet

hafnium-exchange-splunk-csvs IOCs (IP addresses, hashes of web shell aspx files, names of aspx files, user-agents) used in exploiting CVE-2021-26855 courtesy of Volexity and Microsoft See wwwvolexitycom/blog/2021/03/02/active-exploitation-of-microsoft-exchange-zero-day-vulnerabilities/ and wwwmicrosoftcom/security/blog/2021/03/02/hafnium-targeting-exchang

Scan-Vuln-CVE-2021-26855

CVE_2021_26855_Exploit_Hub POC SSRF CVE-2021-26855

2021-march-exchange Info Et repo som samler litt nyttig informasjon ifm Microsoft Exchange-sårbarheter og angrepskampanje JAN - MAR 2021 Ekstern informasjon wwwmicrosoftcom/security/blog/2021/03/02/hafnium-targeting-exchange-servers/ wwwvolexitycom/blog/2021/03/02/active-exploitation-of-microsoft-exchange-zero-day-vulnerabilities/ Scripts / verkt&osl

CVE-2021-26855 PoC for CVE-2021-26855 -Just a checker- Usage python3 CVE-2021-26855py -u mailexamplecom # Checker for CVE-2021-26855: Exchange Server SSRF Vulnerability # Coded by Abdullah AlZahrani Githubcom/0xAbdullah [*] You set target to mailexamplecom [#] This site is vulnerable to CVE-2021-26855

ProxyLogonHashesps1 Checks for aspx Hashes of exploit from CVE-2021-26855, 26858, 26857, and 27065 Hashes from Microsoft (sha256): wwwmicrosoftcom/security/blog/2021/03/02/hafnium-targeting-exchange-servers/ b75f163ca9b9240bf4b37ad92bc7556b40a17e27c2b8ed5c8991385fe07d17d0 097549cf7d0f76f0d99edf8b2d91c60977fd6a96e4b8c3c94b0b1733dc026d3e 2b6f1ebb2208e93ade4a6424555

ProxyLogon PoC of proxylogon chain SSRF(CVE-2021-26855) to write file testanull/PoC_proxyLogonpy webarchiveorg/web/20210310164403/gistgithubcom/testanull/fabd8eeb46f120c4b15f8793617ca7d1

CVE-2021-26855 PoC of proxylogon chain SSRF(CVE-2021-26855) to write file by testanull, censored by github Why does github remove this exploit because it is against the acceptable use policy - but tons of other proof of concept exploits and frameworks are OK? githubcom/rapid7/metasploit-framework Lots of CVE exploit repositories Is it because Github is owned by Micro

CVE-2021-26855 CVE-2021-26855, also known as Proxylogon, is a server-side request forgery (SSRF) vulnerability in Exchange that allows an attacker to send arbitrary HTTP requests and authenticate as the Exchange server According to Orange Tsai, the researcher who discovered the vulnerabilities, CVE-2021-26855 allows code execution when chained with CVE-2021-27065 (see below)

ProxyLogon For Python3 ProxyLogon(CVE-2021-26855+CVE-2021-27065) Exchange Server RCE(SSRF->GetWebShell) usage: python ProxyLogonpy --host=exchangecom --mail=admin@exchangecom python ProxyLogonpy --host=exchangecom --mails=/mailstxt args: --host: target's address --mail: exists user's mail --mails: mails file

HAFHunt Quick powershell script to search for HAFNIUM IOCs for On-Prem Exchange Servers Leverages IOCs listed in Microsoft and Volexcity articles Find ASPX files Find known Webshell names List archived files in C:\ProgramData LogSearch OABGeneratorLog (CVE-2021-26858) LogSearch HttpProxy logs (CVE-2021-26855) LogSearch WindowsEvents (CVE-2021-26857) LogSearch Exchange Logs (C

exchange-0days-202103 IoC determination for exploitation of CVE-2021-26855, CVE-2021-26857, CVE-2021-26858 and CVE-2021-27065

Exchange-HAFNIUM Threat Advisory for the MS Exchange Zero-day Vulnerability Introduction On March 2, 2021 Microsoft has released patches for several critical vulnerabilities for Microsoft Exchange Server that have been found to be exploited in different regions It is highly recommended for all the users running affected versions to update their servers with newly released

ExProlog ProxyLogon Full Exploit Chain PoC (CVE-2021–26855, CVE-2021–26857, CVE-2021–26858, CVE-2021–27065) Usage: exprologpy [OPTIONS] ExProlog - ProxyLogon Full Exploit Chain PoC (CVE-2021–26855, CVE-2021–26857, CVE-2021–26858, CVE-2021–27065) Options: -t, --target TEXT Target MS Exchange Server (eg outlookvictimc

CVE-2021-26855 CVE-2021-26855 ssrf 简单利用 golang 练习 影响版本 Exchange Server 2013 小于 CU23 Exchange Server 2016 小于 CU18 Exchange Server 2019 小于 CU7 利用条件 该漏洞不同于以往的 exchange 漏洞,此漏洞并不需要一个可登录的用户身份,可以在未授权的情况下获取内部用户资源,配合 CVE-2021-27065 可以实现远

proxylogscan This tool to mass scan for a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authentication and impersonating as the admin (CVE-2021-26855) By chaining this bug with another post-auth arbitrary-file-write vulnerability to get code execution (CVE-2021-27065) As a result, an unauthenticated attacker can execute arbitrary commands o

Exch-CVE-2021-26855 ProxyLogon is the formally generic name for CVE-2021-26855, a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authentication and impersonating as the admin We have also chained this bug with another post-auth arbitrary-file-write vulnerability, CVE-2021-27065, to get code execution All affected components are vulnerable by

CVE-2021-26855-CVE-2021-27065 analytics ProxyLogo Mail exchange RCE

ProxyLogon Chaining CVE-2021-26855 and CVE-2021-26857 to exploit Microsoft Exchange

Ladon Scanner For Golang Wiki k8gegeorg/Ladon/LadonGohtml 简介 LadonGo一款开源内网渗透扫描器框架,使用它可轻松一键探测C段、B段、A段存活主机、指纹识别、端口扫描、密码爆破、远程执行、高危漏洞检测等。36版本包含28个模块功能,高危漏洞检测MS17010、SmbGhost,远程执行SshCmd、WinrmCmd、PhpS

proxylogon Proof-of-concept exploit for CVE-2021-26855 and CVE-2021-27065, which allows for unauthenticated remote code execution on Microsoft Exchange as described in the following resources: wwwmicrosoftcom/security/blog/2021/03/02/hafnium-targeting-exchange-servers wwwvolexitycom/blog/2021/03/02/active-exploitation-of-microsoft-exchange-zero-day-vulnerab

shellcollector HAFNIUM campaign: wwwmicrosoftcom/security/blog/2021/03/02/hafnium-targeting-exchange-servers/ CVE-2021-26855 CVE-2021-26857 CVE-2021-27065 CVE-2021-26858 This is a PowerShell script that will locate potential web shells created by the SYSTEM user from 1/1/2021 onwards Simply clone or download shellcollectorps1 and execute in PowerShell with admin pri

CVE-2021-26855-PoC PoC exploit code for CVE-2021-26855 Original code was developed by githubcom/GreyOrder The original repo was deleted shortly after additional features (user enumeration etc) were added Please post a pull request, if you have the latest version CVE-2021-26855 ssrf simple use of golang exercises Affected version: Exchange Server 2013 is less than

CVE-2021-26855-PoC PoC exploit code for CVE-2021-26855 CVE-2021-26855 ssrf simple use of golang exercises Affected version: Exchange Server 2013 is less than CU23 Exchange Server 2016 is less than CU18 Exchange Server 2019 is less than CU7 Conditions of use: This vulnerability is different from previous exchange vulnerabilities This vulnerability does not require a user identi

CVE-2021-26855 CVE-2021-26855 ssrf 简单利用 golang 练习 影响版本 Exchange Server 2013 小于 CU23 Exchange Server 2016 小于 CU18 Exchange Server 2019 小于 CU7 利用条件 该漏洞不同于以往的 exchange 漏洞,此漏洞并不需要一个可登录的用户身份,可以在未授权的情况下获取内部用户资源,配合 CVE-2021-27065 可以实现远

Exchange_IOC_Hunter Description: Hunt for IOCs in IIS Logs - CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065 Artefacts Supported: C2 IP Addresses (used for scanning and exploitation) File Names (observed in exploitation attempts) Usage: powershell \Exchange_IOC_Hunterps1 Updates: This repository will be updated with new IOC's shortly

CVE-2021-26855 CVE-2021-26855 ssrf 简单利用 golang 练习 影响版本 Exchange Server 2013 小于 CU23 Exchange Server 2016 小于 CU18 Exchange Server 2019 小于 CU7 利用条件 该漏洞不同于以往的 exchange 漏洞,此漏洞并不需要一个可登录的用户身份,可以在未授权的情况下获取内部用户资源,配合 CVE-2021-27065 可以实现远

Exchange-Exploit Check for Exchange Server CVEs CVE-2021-26855, CVE-2021-26857, CVE-2021-26858 and CVE-2021-27065 nmap --script http-vuln-exchange [TARGET]

Hafnium Microsoft Exchange NOTE: Original scripts are available at John Hammond's Github Gist Some Technical Details CVEs Listed CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065 CVE-2021-26855 is a server-side request forgery (SSRF) vulnerability in Exchange which allowed the attacker to send arbitrary HTTP requests and authenticate as the Exchange server

HAFNIUM CVE-2021-26855 msrcmicrosoftcom/update-guide/vulnerability/CVE-2021-26855 CVE-2021-26855 is a server-side request forgery (SSRF) vulnerability in Exchange which allowed the attacker to send arbitrary HTTP requests and authenticate as the Exchange server CVE-2021-26857 msrcmicrosoftcom/update-guide/vulnerability/CVE-2021-26857 CVE-2021-26857 i

HAFNIUM CVE-2021-26855 msrcmicrosoftcom/update-guide/vulnerability/CVE-2021-26855 CVE-2021-26855 is a server-side request forgery (SSRF) vulnerability in Exchange which allowed the attacker to send arbitrary HTTP requests and authenticate as the Exchange server CVE-2021-26857 msrcmicrosoftcom/update-guide/vulnerability/CVE-2021-26857 CVE-2021-26857 i

Operation Exchange Marauder - An aggregated view for Defenders Introduction Advisories, Analysis, and Countermeasures CVE's Exploited Tools Used in the Attack Methodology of Attack Detection CVE Detections Microsoft defender Queries Azure Sentinel Detections Sentinel Queries Powershell Queries STIX Object Indicators IP addresses Hashes Paths Web Shell Names YARA Rule

Detect webshells dropped on Microsoft Exchange servers after 0day compromises This script looks for webshells dropped on Microsoft Exchange servers while they were vulnerable to following CVE's: CVE-2021-26855, pre-auth SSRF, CVSS:30 91 / 84 CVE-2021-26857, insecure deserialization leading to privilege escalation to SYSTEM level, CVSS:30 78 / 72 CVE-2021-26858, post

ZIRCONIUM ZIRCONIUM has been created to scan for Indicators of Compromise (IOCs) on Exchange Servers for signs of Zero-Day exploits used by HAFNIUM ZIRCONIUM will search for: CVE-2021-26855 CVE-2021-26958 CVE-2021-26857 CVE-2021-27027065 Suspicious dmp Files aspnet Files Found in inetpub and Exchange File Paths Usage Download the lastest version of ZIRCONIUM: githu

Important information regarding Exchange Server (2010, 2013, 2016, 2019) 0-day exploits Today (Tuesday 2nd March 2021), Microsoft released patches for multiple different on-premises Microsoft Exchange Server zero-day vulnerabilities that are being exploited by a nation-state affiliated group The vulnerabilities exist in on-premises Exchange Servers 2010, 2013, 2016, and 2019

alt3kxgithubio RedTeamer | PentTester | Bug Bounty | 0day guy! | Researcher | Lone Wolf githubcom/alt3kx My Exploit-db reference at: wwwexploit-dbcom/author/?a=1074 wwwexploit-dbcom/author/?a=9576 A handy collection of my public Exploits & CVE's, all available on wwwexploit-dbcom and cvemitreorg CVE's

PoC in GitHub 2021 CVE-2021-1056 (2021-01-07) NVIDIA GPU Display Driver for Linux, all versions, contains a vulnerability in the kernel mode layer (nvidiako) in which it does not completely honor operating system file system permissions to provide GPU device-level isolation, which may lead to denial of service or information disclosure pokerfaceSad/CVE-2021-1056 CVE-2021-

Recent Articles

Microsoft Exchange Servers See ProxyLogon Patching Frenzy
Threatpost • Tara Seals • 24 Mar 2021

The patching level for Microsoft Exchange Servers that are vulnerable to the ProxyLogon group of security bugs has reached 92 percent, according to Microsoft.
The computing giant tweeted out the stat earlier this week – though of course patching won’t fix already-compromised machines. Still, that’s an improvement of 43 percent just since last week, Microsoft pointed out (using telemetry from RiskIQ).

ProxyLogon consists of four flaws (CVE-2021-26855, CVE-2021-26857, CVE...

Microsoft Defender adds automatic Exchange ProxyLogon mitigation
BleepingComputer • Sergiu Gatlan • 19 Mar 2021

Microsoft Defender Antivirus will now protect unpatched on-premises Exchange servers from ongoing attacks by automatically mitigating the actively exploited CVE-2021-26855 vulnerability.
Customers running System Center Endpoint Protection on their servers will also be protected through the same automated mitigation process.
"The Exchange security update is still the most comprehensive way to protect your servers from these attacks and others fixed in earlier releases," Microsoft said...

Exchange Cyberattacks Escalate as Microsoft Rolls One-Click Fix
Threatpost • Tara Seals • 16 Mar 2021

As dangerous attacks accelerate against Microsoft Exchange Servers in the wake of the disclosure around the ProxyLogon group of security bugs, a public proof-of-concept (PoC) whirlwind has started up. It’s all leading to a feeding frenzy of cyber-activity.
The good news, however, is that Microsoft has issued a one-click mitigation and remediation tool in light of the ongoing swells of attacks.
Researchers said that while advanced persistent threats (APTs) were the first to the game...

Microsoft Exchange Exploits Pave a Ransomware Path
Threatpost • Lindsey O'Donnell • 12 Mar 2021

Cybercriminals are now using compromised Microsoft Exchange servers as a foothold to deploy a new ransomware family called DearCry, Microsoft has warned.
The ransomware is the latest threat to beleaguer vulnerable Exchange servers, emerging shortly after Microsoft issued emergency patches in early March for four Microsoft Exchange flaws. The flaws can be chained together to create a pre-authentication remote code execution (RCE) exploit – meaning that attackers can take over servers wi...

Microsoft Exchange Servers Face APT Attack Tsunami
Threatpost • Tara Seals • 11 Mar 2021

Recently patched Microsoft Exchange vulnerabilities are under fire from at least 10 different advanced persistent threat (APT) groups, all bent on compromising email servers around the world. Overall exploitation activity is snowballing, according to researchers.
Microsoft said in early March that it had spotted multiple zero-day exploits in the wild being used to attack on-premises versions of Microsoft Exchange Server. Four flaws can be chained together to create a pre-authentication rem...

Exchange servers under siege from at least 10 APT groups
welivesecurity • 10 Mar 2021

On 2021-03-02, Microsoft released out-of-band patches for Microsoft Exchange Server 2013, 2016 and 2019. These security updates fixed a pre-authentication remote code execution (RCE) vulnerability chain (CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065) that allows an attacker to take over any reachable Exchange server, without even knowing any valid account credentials. We have already detected webshells on more than 5,000 email servers as of the time of writing, and according...

Microsoft Patch Tuesday Updates Fix 14 Critical Bugs
Threatpost • Lindsey O'Donnell • 09 Mar 2021

Microsoft has released its regularly scheduled March Patch Tuesday updates, which address 89 security vulnerabilities overall.
Included in the slew are 14 critical flaws and 75 important-severity flaws. Microsoft also included five previously disclosed vulnerabilities, which are being actively exploited in the wild.
Four of the actively exploited flaws (CVE-2021-26855, CVE-2021-26857, CVE-2021-26858 and CVE-2021-27065), found in Microsoft Exchange, were disclosed as part of an emerge...

How Symantec Stops Microsoft Exchange Server Attacks
Symantec Threat Intelligence Blog • Threat Hunter Team • 08 Mar 2021

Symantec's Intrusion Protection technology will block all attempted exploits of critical vulnerabilities.

Posted: 8 Mar, 20214 Min ReadThreat Intelligence SubscribeHow Symantec Stops Microsoft Exchange Server AttacksSymantec's Intrusion Protection technology will block all attempted exploits of critical vulnerabilities. Users of Microsoft Exchange Server are advised to update to the latest version immediately, as a growing number of attackers are attempting to exploit four recently patched zero-day vulnerabilities in the software.

Microsoft rele...

This new Microsoft tool checks Exchange Servers for ProxyLogon hacks
BleepingComputer • Lawrence Abrams • 06 Mar 2021

Microsoft has released a PowerShell script that admins can use to check whether the recently disclosed ProxyLogon vulnerabilities have hacked a Microsoft Exchange server.
On March 2nd, Microsoft released out-of-band emergency security updates to fix four zero-day vulnerabilities actively used in
. These vulnerabilities are tracked as CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065.
When chained together, these vulnerabilities are known as '
' and allow t...

Microsoft rushes out fixes for four zero‑day flaws in Exchange Server
welivesecurity • 04 Mar 2021

Microsoft has rushed out emergency updates to address four zero-day flaws affecting Microsoft Exchange Server versions 2013, 2016, and 2019. Threat actors have been observed exploiting the vulnerabilities in the wild to access on-premises Exchange servers, which allowed them to steal emails, download data, and compromise machines with malware for long-term access to the victim networks. Due to the severity of the threat, the Redmond tech titan is urging users to patch their systems immediately.<...

CISA Orders Federal Agencies to Patch Exchange Servers
Threatpost • Tara Seals • 04 Mar 2021

Hot on the heels of Microsoft’s announcement about active cyber-espionage campaigns that are exploiting four serious security vulnerabilities in Microsoft Exchange Server, the U.S. government is mandating patching for the issues.
The news comes as security firms report escalating numbers of related campaigns led by sophisticated adversaries against a range of high-value targets, especially in the U.S.
The Cybersecurity and Infrastructure Security Agency (CISA) has issued an emergen...

Detection and Response to Exploitation of Microsoft Exchange Zero-Day Vulnerabilities
Fireeye Threat Research • by Matt Bromiley, Chris DiGiamo, Andrew Thompson, Robert Wallace • 04 Mar 2021

Beginning in January 2021, Mandiant Managed Defense observed multiple instances of abuse of Microsoft Exchange Server within at least one client environment. The observed activity included creation of web shells for persistent access, remote code execution, and reconnaissance for endpoint security solutions. Our investigation revealed that the files created on the Exchange servers were owned by the user NT AUTHORITY\SYSTEM, a privileged local account on the Windows operating system. Furthermore,...

State hackers rush to exploit unpatched Microsoft Exchange servers
BleepingComputer • Sergiu Gatlan • 03 Mar 2021

Multiple state-sponsored hacking groups are actively exploiting critical Exchange bugs Microsoft patched Tuesday via emergency out-of-band security updates.
Microsoft addressed four zero-days (CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065) exploited in the wild and three other vulnerabilities (CVE-2021-27078, CVE-2021-26854, and CVE-2021-26412).
Advanced persistent threat (APT) groups are currently using "at least" the CVE-2021-26855 Microsoft Exchange Server vul...

Microsoft fixes actively exploited Exchange zero-day bugs, patch now
BleepingComputer • Lawrence Abrams • 02 Mar 2021

Microsoft has released emergency out-of-band security updates for all supported Microsoft Exchange versions that fix four zero-day vulnerabilities actively exploited in targeted attacks.
These four zero-day vulnerabilities are chained together to gain access to Microsoft Exchange servers, steal email, and plant further malware for increased access to the network.
For the attack to work, remote attackers would need to access an on-premise Microsoft Exchange server on port 443. If acce...

Microsoft releases ProxyLogon updates for unsupported Exchange Servers
BleepingComputer • Sergiu Gatlan • 01 Jan 1970

Microsoft has released security updates for Microsoft Exchange servers running unsupported Cumulative Update versions vulnerable to ProxyLogon attacks.
These additional security updates are meant to be installed only on machines running Exchange Server versions not supported by the original Match 2021 security patches released a week ago, only if the admin can't find an update path to a supported version.
Applying these security updates will only address the
 (tracked as CVE...

The Microsoft Exchange hacks: How they started and where we are
BleepingComputer • Ionut Ilascu • 01 Jan 1970

The emergency patches for the recently disclosed critical vulnerabilities in Microsoft Exchange email server
and organizations had little time to prepare before en masse exploitation began.
Named ProxyLogon, the bug has been exploited in the wild even before Microsoft received the vulnerability report, giving attackers a two-month head start to breach targets before security updates became available.
Vulnerable servers are hot targets for a wide spectrum of threat actor group...

Microsoft's MSERT tool now finds web shells from Exchange Server attacks
BleepingComputer • Lawrence Abrams • 01 Jan 1970

Microsoft has pushed out a new update for their Microsoft Safety Scanner (MSERT) tool to detect web shells deployed in the recent Exchange Server attacks.
On March 2nd, Microsoft disclosed that four Exchange Server zero-day vulnerabilities were being used in 
. These vulnerabilities are tracked as CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065.
Known as 'ProxyLogon,' these vulnerabilities are being used by Chinese state-sponsored threat actors to steal mailboxe...

The Register

Patch Tuesday A week after Microsoft warned that four zero-day flaws and three others in its Exchange Server were being actively exploited and issued out-of-band remediation, the cloudy Windows biz has delivered software fixes to address 82 other vulnerabilities as part of its monthly Patch Tuesday ritual.
All told, that makes 89 CVEs for the month, 14 of which have been deemed critical. Microsoft says two of these vulnerabilities (CVE-2021-26411 and CVE-2021-27077) are publicly known and ...

The Register

On Wednesday, shortly after security researcher Nguyen Jang posted a proof-of-concept exploit on GitHub that abuses a Microsoft Exchange vulnerability revealed earlier this month, GitHub, which is owned by Microsoft, removed code, to the alarm of security researchers.
The PoC code, something short of an actual functioning exploit, consisted of a 169-line Python file. It took advantage of CVE-2021-26855, a Microsoft Exchange Server flaw that allows an attacker to bypass authentication and a...