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Exchange server£º2010/2013/2016/2019
Exchange online£º²»ÊÜÓ°Ïì¡£¡£¡£¡£¡£¡£

Îó²îÏêÇé

1.    CVE-2021-26855: ·þÎñ¶ËÇëÇóαÔìÎó²î

Exchange ·þÎñÆ÷¶ËÇëÇóαÔ죨SSRF£©Îó²î£¬£¬£¬£¬£¬£¬£¬Ê¹ÓôËÎó²îµÄ¹¥»÷ÕßÄܹ»·¢ËÍí§Òâ HTTP ÇëÇó²¢Í¨¹ý Exchange Server ¾ÙÐÐÉí·ÝÑéÖ¤¡£¡£¡£¡£¡£¡£

2.   CVE-2021-26857: ÐòÁл¯Îó²î

Exchange ·´ÐòÁл¯Îó²î£¬£¬£¬£¬£¬£¬£¬¸ÃÎó²îÐèÒªÖÎÀíԱȨÏÞ£¬£¬£¬£¬£¬£¬£¬Ê¹ÓôËÎó²îµÄ¹¥»÷Õß¿ÉÒÔÔÚ Exchange ·þÎñÆ÷ÉÏÒÔ SYSTEM Éí·ÝÔËÐдúÂë¡£¡£¡£¡£¡£¡£

3.   CVE-2021-26858: í§ÒâÎļþдÈëÎó²î

Exchange ÖÐÉí·ÝÑéÖ¤ºóµÄí§ÒâÎļþдÈëÎó²î¡£¡£¡£¡£¡£¡£¹¥»÷Õßͨ¹ý Exchange ·þÎñÆ÷½ø ÐÐÉí·ÝÑéÖ¤ºó£¬£¬£¬£¬£¬£¬£¬¿ÉÒÔʹÓôËÎó²î½«ÎļþдÈë·þÎñÆ÷ÉϵÄÈκη¾¶¡£¡£¡£¡£¡£¡£¸ÃÎó²î¿ÉÒÔ ÅäºÏ CVE-2021-26855 SSRF Îó²î¾ÙÐÐ×éºÏ¹¥»÷¡£¡£¡£¡£¡£¡£

4.   CVE-2021-27065: í§ÒâÎļþдÈëÎó²î

Exchange ÖÐÉí·ÝÑéÖ¤ºóµÄí§ÒâÎļþдÈëÎó²î¡£¡£¡£¡£¡£¡£¹¥»÷Õßͨ¹ý Exchange ·þÎñÆ÷½ø ÐÐÉí·ÝÑéÖ¤ºó£¬£¬£¬£¬£¬£¬£¬¿ÉÒÔʹÓôËÎó²î½«ÎļþдÈë·þÎñÆ÷ÉϵÄÈκη¾¶¡£¡£¡£¡£¡£¡£¸ÃÎó²î¿ÉÒÔ ÅäºÏ CVE-2021-26855 SSRF Îó²î¾ÙÐÐ×éºÏ¹¥»÷¡£¡£¡£¡£¡£¡£

Çå¾²½¨Òé

΢ÈíÒÑÐû²¼Ïà¹ØÇå¾²¸üУ¬£¬£¬£¬£¬£¬£¬Óû§¿É¸ú½øÒÔÏÂÁ´½Ó¾ÙÐÐÉý¼¶:

CVE-2021-26855: https://msrc.microsoft.com/update-guide/vulnerability/CVE2021-26855

CVE-2021-26857: https://msrc.microsoft.com/update-guide/vulnerability/CVE2021-26857
CVE-2021-26858: https://msrc.microsoft.com/update-guide/vulnerability/CVE2021-26858
CVE-2021-27065: https://msrc.microsoft.com/update-guide/vulnerability/CVE2021-27065

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01 CVE-2021-26855

¿ÉÒÔͨ¹ýÒÔÏÂExchange HttpProxyÈÕÖ¾¾ÙÐмì²â£º

%PROGRAMFILES%\Microsoft\Exchange Server\V15\Logging\HttpProxy

¿ÉÒÔͨ¹ýÔÚÈÕÖ¾ÌõÄ¿ÖÐËÑË÷AuthenticatedUserÊÇ·ñΪ¿Õ²¢ÇÒAnchorMailboxÊÇ·ñ°üÀ¨ServerInfo?* / *ģʽʶ±ðÎó²îʹÓᣡ£¡£¡£¡£¡£ÒÔÏÂPowershell¿ÉÖ±½Ó¾ÙÐÐÈÕÖ¾¼ì²â£¬£¬£¬£¬£¬£¬£¬²¢¼ì²éÊÇ·ñÊܵ½¹¥»÷£º

Import-Csv-Path(Get-ChildItem-Recurse-Path “$env:PROGRAMFILES\Microsoft\Exchange Server\V15\Logging\HttpProxy”- Filter ‘*.log’).FullName | Where-Object {  $_.AuthenticatedUser -eq ” -and $_.AnchorMailbox -like ‘ServerInfo~*/*’ } | select DateTime, AnchorMailbox

ÈôÊǼì²âµ½ÁËÈëÇÖ£¬£¬£¬£¬£¬£¬£¬¿ÉÒÔͨ¹ý¼ì²âAnchorMailbox·¾¶ÖÐÖ¸¶¨Ìض¨Ó¦ÓóÌÐòµÄÈÕÖ¾À´»ñÈ¡¹¥»÷Õß½ÓÄÉÁËÄÄЩÔ˶¯£º

%PROGRAMFILES%\Microsoft\Exchange Server\V15\Logging

02 CVE-2021-26858

ͨ¹ýExchangeÈÕÖ¾Îļþ¼ì²âCVE-2021-26858ʹÓãº

ÈÕ־Ŀ¼£º
C:\Program Files\Microsoft\Exchange Server\V15\Logging\OABGeneratorLog

¿Éͨ¹ýÒÔÏÂÏÂÁî¾ÙÐпìËÙä¯ÀÀ£¬£¬£¬£¬£¬£¬£¬²¢¼ì²éÊÇ·ñÊܵ½¹¥»÷£º

findstr /snip /c:”Download failed and temporary file” “%PROGRAMFILES%\Microsoft\Exchange Server\V15\Logging\OABGeneratorLog\*.log”

03 CVE-2021-26857

ͨ¹ýWindowsÓ¦ÓóÌÐòÊÂÎñÈÕÖ¾¼ì²âCVE-2021-26857ʹÓ㬣¬£¬£¬£¬£¬£¬Ê¹Óô˷´ÐòÁл¯¹ýʧ½«½¨Éè¾ßÓÐÒÔÏÂÊôÐÔµÄÓ¦ÓóÌÐòÊÂÎñ£º

ȪԴ£ºMSExchangeͳһÐÂÎÅ
EntryType£º¹ýʧ
ÊÂÎñÐÂÎÅ°üÀ¨£ºSystem.InvalidCastExceptio

¸ÃÎó²îµ¥¶ÀʹÓÃÄѶÈÉԸߣ¬£¬£¬£¬£¬£¬£¬¿ÉʹÓÃÒÔÏÂÏÂÁîÔÚÓ¦ÓóÌÐòÊÂÎñÈÕÖ¾ÖÐÅÌÎÊÕâЩÈÕÖ¾ÌõÄ¿£¬£¬£¬£¬£¬£¬£¬²¢¼ì²éÊÇ·ñÊܵ½¹¥»÷¡£¡£¡£¡£¡£¡£

Get-EventLog -LogName Application -Source “MSExchange Unified Messaging” -EntryType Error | Where-Object { $_.Message -like “*System.InvalidCastException*” }

04 CVE-2021-27065

ͨ¹ýÒÔÏÂExchangeÈÕÖ¾Îļþ¼ì²âCVE-2021-27065ʹÓ㬣¬£¬£¬£¬£¬£¬

C£º\ Program Files \ Microsoft \ Exchange Server \ V15 \ Logging \ ECP \ Server

ËùÓÐSet- <AppName> VirtualDirectoryÊôÐÔ¶¼²»Ó¦°üÀ¨¾ç±¾¡£¡£¡£¡£¡£¡£InternalUrlºÍExternalUrlÓ¦¸Ã½öÊÇÓÐÓÃUris¡£¡£¡£¡£¡£¡£

ͨ¹ýpowershellÏÂÁî¾ÙÐÐÈÕÖ¾¼ì²â£¬£¬£¬£¬£¬£¬£¬²¢¼ì²éÊÇ·ñÔâµ½¹¥»÷:

Select-String -Path “$env:PROGRAMFILES\Microsoft\Exchange Server\V15\Logging\ECP\Server\*.log” -Pattern ‘Set-.+VirtualDirectory’

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