cbcvebase.
CVE-2016-3304
published 2016-08-09

CVE-2016-3304: The Windows font library in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Office 2007 SP3, Office 2010 SP2, Word Viewer…

PriorityP266high7.8CVSS 3.0
AVLACLPRNUIRSUCHIHAH
EXPLOIT
EPSS
50.51%
98.8th percentile
The Windows font library in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Office 2007 SP3, Office 2010 SP2, Word Viewer, Skype for Business 2016, Lync 2013 SP1, Lync 2010, Lync 2010 Attendee, and Live Meeting 2007 Console allows remote attackers to execute arbitrary code via a crafted embedded font, aka "Windows Graphics Component RCE Vulnerability," a different vulnerability than CVE-2016-3303.

Affected

21 ranges
VendorProductVersion rangeFixed in
microsoftlive_meeting
microsoftlync
microsoftlync
microsoftoffice
microsoftoffice
microsoftskype_for_business
microsoftwindows_server_2008
msrcmicrosoft_live_meeting_2007_console
msrcmicrosoft_lync_2010
msrcmicrosoft_lync_2010_attendee
msrcmicrosoft_lync_2013_service_pack_1
msrcmicrosoft_lync_basic_2013_service_pack_1
msrcmicrosoft_office_2007_service_pack_3
msrcmicrosoft_office_2010_service_pack_2
msrcmicrosoft_office_word_viewer
msrcskype
msrcwindows_7
msrcwindows_server_2008
msrcwindows_server_2008_r2
msrcwindows_vista_service_pack_2
msrcwindows_vista_x64_edition_service_pack_2

Detection & IOCsextracted from sources · hover to see the quote

hashc861ee277cd4e2d914740000161956ef
pathC:\Windows\winsxs\x86_microsoft.windows.gdiplus_6595b64144ccf1df_1.1.7601.23407_none_5c02a2f5a011f9be\GdiPlus.dll
filenamepoc.emf
  • Trigger condition: EMF records EMR_EXTTEXTOUTA or EMR_POLYTEXTOUTA with an offDx field pointing to an undersized intercharacter spacing array, combined with a DBCS font charset (e.g. SHIFTJIS_CHARSET) and lead bytes in the text string, causes heap buffer overflow in GDI+ during EMF-to-EMF+ conversion.
  • Exploitation requires a specially crafted .EMF file with a non-standard DBCS encoding (e.g. SHIFTJIS_CHARSET) and lead bytes to reduce MultiByteToWideChar() return value below nChars, triggering the array rewrite overflow path.
  • Attack vectors include opening a crafted Office document (e.g. PowerPoint .pptx) or visiting a web page embedding a malicious EMF font; monitor for Office processes (POWERPNT.EXE, etc.) loading crafted EMF files that invoke GdipConvertToEmfPlus.
  • Vulnerable validation logic: the record size check only verifies 4 bytes at offDx instead of 4*nChars bytes; detection/fuzzing should focus on EMF records where (record_size - offDx) < 4*nChars.
  • ·The vulnerable GdiPlus.dll version analysed is 1.1.7601.23407 (pre-patch) on Windows 7 64-bit; the vulnerability also affects Vista SP2, Server 2008 SP2/R2 SP1, Office 2007 SP3, Office 2010 SP2, Word Viewer, Skype for Business 2016, Lync 2013 SP1, Lync 2010, Lync 2010 Attendee, and Live Meeting 2007 Console.
  • ·Exploit status per Microsoft: not yet exploited in the wild at time of publication, but rated 'Exploitation More Likely' for both latest and older software releases.
  • ·This is a different vulnerability from CVE-2016-3303, though both affect the Windows font library in the same set of products.

CVSS provenance

nvdv3.07.8HIGHCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
nvdv2.09.3CRITICALAV:N/AC:M/Au:N/C:C/I:C/A:C
vendor_msrc8.8HIGH
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