Description

A heap over flow was found in pcapfix in function fix_pcapng() in pcapng.c at line 216

Test version : 1.1.6 [2fe168e] Test env: gcc 9.3.0 ubuntu 20.04 x86-64

Proof of Concept

CFLAGS="-fsanitize=address" make

./pcapfix poc

poc is attatched in reference link

==603793==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000000017 at pc 0x000000322134 bp 0x7fff77333d70 sp 0x7fff77333d68
WRITE of size 8 at 0x602000000017 thread T0
#0 0x322133 in fix_pcapng /home/chiba/pcapfix/pcapng.c:216:5
#1 0x303b1c in main /home/chiba/pcapfix/pcapfix.c
#2 0x7f5fe13380b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
#3 0x255f7d in _start (/home/chiba/pcapfix/pcapfix-afl+0x255f7d)

0x602000000017 is located 1 bytes to the right of 6-byte region [0x602000000010,0x602000000016)
allocated by thread T0 here:
#0 0x2cffed in malloc (/home/chiba/pcapfix/pcapfix-afl+0x2cffed)
#1 0x311fa0 in fix_pcapng /home/chiba/pcapfix/pcapng.c:213:17
#2 0x303b1c in main /home/chiba/pcapfix/pcapfix.c
#3 0x7f5fe13380b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/chiba/pcapfix/pcapng.c:216:5 in fix_pcapng
Shadow bytes around the buggy address:
0x0c047fff7fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c047fff8000: fa fa[06]fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
==603793==ABORTING

Impact

This vulnerability is capable of crashing the software, causing memory corruption, and any other unintended consequences of reading past the end of the buffer.