Exploit the possiblities
Showing 1 - 1 of 1 RSS Feed

Operating System: Os:microsoft

Microsoft GDI+ Untrusted Data Filter Bypass
Posted Jul 27, 2016
Authored by Google Security Research, mjurczyk

The GDI+ library can handle bitmaps originating from untrusted sources through a variety of attack vectors, like EMF files, which may embed bitmaps in records such as EMR_PLGBLT, EMR_BITBLT, EMR_STRETCHBLT, EMR_STRETCHDIBITS etc. The GDI+ implementation supports bitmaps compressed with the BI_RLE8 (8-bit Run-Length Encoding) compression algorithm, and performs the actual decompression in the gdiplus!DecodeCompressedRLEBitmap function. The buffer allocated to store the decompressed pixels is not cleared during or directly after the HeapAlloc() call, which causes it contain heap metadata and leftover data of previous allocations. The RLE compression algorithm makes it possible to skip some (in an extreme case: all) bytes in the output buffer; this could be achieved by using escape codes such as "End of line", "End of bitmap" or "Delta". If we start the compressed stream with the "End of bitmap" marker, the entirety of the memory region will remain uninitialized, which will in turn lead to displaying junk bytes as pixels. In the context of GDI+ clients which make it possible to read the rendered pixels back and send them to an attacker or use as part of a larger exploit chain, the bug could result in disclosure of sensitive data or defeat of exploit mitigations such as ASLR.

tags | exploit
systems | microsoft
MD5 | 5f3df3c509e8dd1e7a0649e7c2fbbf14
Page 1 of 1
Back1Next

Want To Donate?


Bitcoin: 18PFeCVLwpmaBuQqd5xAYZ8bZdvbyEWMmU

File Archive:

February 2018

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Feb 1st
    15 Files
  • 2
    Feb 2nd
    15 Files
  • 3
    Feb 3rd
    15 Files
  • 4
    Feb 4th
    13 Files
  • 5
    Feb 5th
    16 Files
  • 6
    Feb 6th
    15 Files
  • 7
    Feb 7th
    15 Files
  • 8
    Feb 8th
    15 Files
  • 9
    Feb 9th
    18 Files
  • 10
    Feb 10th
    8 Files
  • 11
    Feb 11th
    8 Files
  • 12
    Feb 12th
    17 Files
  • 13
    Feb 13th
    15 Files
  • 14
    Feb 14th
    15 Files
  • 15
    Feb 15th
    17 Files
  • 16
    Feb 16th
    18 Files
  • 17
    Feb 17th
    37 Files
  • 18
    Feb 18th
    2 Files
  • 19
    Feb 19th
    16 Files
  • 20
    Feb 20th
    16 Files
  • 21
    Feb 21st
    15 Files
  • 22
    Feb 22nd
    16 Files
  • 23
    Feb 23rd
    31 Files
  • 24
    Feb 24th
    0 Files
  • 25
    Feb 25th
    0 Files
  • 26
    Feb 26th
    0 Files
  • 27
    Feb 27th
    0 Files
  • 28
    Feb 28th
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2018 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close