Heap corruption can occur when the WhatsApp mobile application receives a malformed RTP packet.
08-31 15:43:50.721 9428 9713 F libc : Fatal signal 11 (SIGSEGV), code 1, fault addr 0x7104200000 in tid 9713 (Thread-11)
08-31 15:43:50.722 382 382 W : debuggerd: handling request: pid=9428 uid=10119 gid=10119 tid=9713
08-31 15:43:50.818 9720 9720 F DEBUG : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
08-31 15:43:50.818 9720 9720 F DEBUG : Build fingerprint: 'google/angler/angler:7.1.2/N2G48H/natash11071827:userdebug/dev-keys'
08-31 15:43:50.818 9720 9720 F DEBUG : Revision: '0'
08-31 15:43:50.818 9720 9720 F DEBUG : ABI: 'arm64'
08-31 15:43:50.818 9720 9720 F DEBUG : pid: 9428, tid: 9713, name: Thread-11 >>> com.whatsapp <<<
08-31 15:43:50.818 9720 9720 F DEBUG : signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x7104200000
08-31 15:43:50.819 9720 9720 F DEBUG : x0 00000071041ffde8 x1 00000071047796b0 x2 0000000000000000 x3 0000000000000030
08-31 15:43:50.819 9720 9720 F DEBUG : x4 0000000000000000 x5 0000000000000040 x6 00000071041fffd8 x7 8181818181818181
08-31 15:43:50.819 9720 9720 F DEBUG : x8 8181818181818181 x9 8181818181818181 x10 8181818181818181 x11 8181818181818181
08-31 15:43:50.819 9720 9720 F DEBUG : x12 8181818181818181 x13 8181818181818181 x14 8181818181818181 x15 0000000000000000
08-31 15:43:50.819 9720 9720 F DEBUG : x16 0000007110a468a0 x17 000000712f3b0908 x18 0000000000000000 x19 0000000000000280
08-31 15:43:50.819 9720 9720 F DEBUG : x20 00000071088744a8 x21 0000000000000280 x22 00000071256a5a28 x23 0000007104ff9b70
08-31 15:43:50.819 9720 9720 F DEBUG : x24 000000000000100d x25 000000000000120d x26 0000007104779480 x27 0000007108830828
08-31 15:43:50.819 9720 9720 F DEBUG : x28 0000000000151f80 x29 00000071043fe540 x30 000000711060a010
08-31 15:43:50.819 9720 9720 F DEBUG : sp 00000071043fe320 pc 000000712f3b0a5c pstate 0000000060000000
08-31 15:43:50.825 9720 9720 F DEBUG :
08-31 15:43:50.825 9720 9720 F DEBUG : backtrace:
08-31 15:43:50.825 9720 9720 F DEBUG : #00 pc 000000000001aa5c /system/lib64/libc.so (memcpy+340)
08-31 15:43:50.825 9720 9720 F DEBUG : #01 pc 00000000000c500c /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #02 pc 00000000000c7d60 /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #03 pc 00000000000f88d4 /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #04 pc 00000000000f6948 /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #05 pc 00000000000f0ef4 /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #06 pc 00000000000f0630 /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #07 pc 00000000000eef3c /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #08 pc 00000000001272e0 /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #09 pc 0000000000303d20 /data/app/com.whatsapp-2/lib/arm64/libwhatsapp.so
08-31 15:43:50.825 9720 9720 F DEBUG : #10 pc 0000000000068734 /system/lib64/libc.so (_ZL15__pthread_startPv+208)
08-31 15:43:50.825 9720 9720 F DEBUG : #11 pc 000000000001da7c /system/lib64/libc.so (__start_thread+16)
This issue can occur when a WhatsApp user accepts a call from a malicious peer. It affects both the Android and iPhone clients.
To reproduce the issue:
1) Apply the attached patch to libwhatsapp.so in the Android application using bsdiff. this patch intercepts a memcpy right before srtp_protect is called, and alters the RTP buffer. The SHA1 of the original library I used was cfdb0266cbd6877e5d146ddd59fa83ebccdd013d, and the SHA1 of the modified library is 042256f240367eaa4a096527d1afbeb56ab2eeb4.
2) Build the attached file, natalie2.c for the Android device the application is running on, and copy it to /data/data/com.whatsapp/libn.so.
3) Copy the files in the attached folder into /data/data/com.whatsapp/files so that /data/data/com.whatsapp/files/t0 is a valid location.
4) Restart WhatsApp and call the target device and pick up the call. The deivce will crash in a few seconds.
Logs from the crashes on Android and iPhone are attached. Note that I modified the Android target binary to disable WhatsApp's custom crash handling. The iPhone WhatsApp install was unmodified.
Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/45579.zip
