Exploit-DB #37741
Description: Apple Mac OSX Keychain - EXC_BAD_ACCESS Denial of Service
Type: dos
Platform: osx
Date: 2015-08-08
Author: Juan Sacco

Exploit:
# Exploit Title: OSX Keychain - EXC_BAD_ACCESS
# Date: 22/07/2015
# Exploit Author: Juan Sacco
# Vendor Homepage: https://www.apple.com
# Software Link: https://www.apple.com/en/downloads/
# Version: 9.0 (55161)
# Tested on: OSX Yosemite 10.10.4
# CVE : None

# History - Reported to product-security@apple.com 20 Jul 2015
# Be careful: Crashing the Keychain will affect the user ability to use
Keychain stored passwords.

# How to reproduce it manually
1. Select a certificate, right click "New certificate preference.."
2. Under "Location or Email address:" add random values +9000
3. Click on Add to conduct the PoC manually

# Technically:
Performing @selector(addCertificatePreference:) from sender NSButton
0x608000148cf0

# Exception type
Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
Exception Codes:       KERN_PROTECTION_FAILURE at 0x00007fff4d866828
External Modification Warnings:
VM Regions Near 0x7fff4d866828:
    MALLOC_SMALL           00007f9e7d[PII_REDACTED]7f9e80000000 [ 48.0M]
rw-/rwx SM=PRV
--> STACK GUARD            00007fff4c7de000-00007fff4ffde000 [ 56.0M]
---/rwx SM=NUL  stack guard for thread 0
    Stack                  00007fff4ffde000-00007fff507de000 [ 8192K]
rw-/rwx SM=COW  thread 0

(lldb)
Process 490 resuming
Process 490 stopped

* thread #1: tid = 0x19b7, 0x00007fff92c663c3
Security`SecCertificateSetPreference + 325, queue =
'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=2,
address=0x7fff4d866828)

    frame #0: 0x00007fff92c663c3 Security`SecCertificateSetPreference + 325

Security`SecCertificateSetPreference:

->  0x7fff92c663c3 <+325>: callq  0x7fff92cf18b2            ; symbol stub
for: CFStringGetCString
    0x7fff92c663c8 <+330>: movq   %rbx, -0x670(%rbp)
    0x7fff92c663cf <+337>: testb  %al, %al
    0x7fff92c663d1 <+339>: jne    0x7fff92c663d8            ; <+346>

Process:               Keychain Access [598]
Path:                  /Applications/Utilities/Keychain
Access.app/Contents/MacOS/Keychain Access
Identifier:            com.apple.keychainaccess
Version:               9.0 (55161)
Build Info:            KeychainAccess[PII_REDACTED]0000000~620
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           Keychain Access [598]
User ID:               501

Date/Time:             2015-07-28 13:32:05.183 +0200
OS Version:            Mac OS X 10.10.4 (14E46)
Report Version:        11
Anonymous UUID:        08523B58-1EF8-DC4A-A7D7-CB31074E4395
Crashed Thread:        0  Dispatch queue: com.apple.main-thread

VM Regions Near 0x7fff507776c8:
    MALLOC_SMALL           00007ff93c[PII_REDACTED]7ff93e000000 [ 24.0M]
rw-/rwx SM=PRV
--> STACK GUARD            00007fff4e5d7000-00007fff51dd7000 [ 56.0M]
---/rwx SM=NUL  stack guard for thread 0
    Stack                  00007fff51dd7000-00007fff525d7000 [ 8192K]
rw-/rwx SM=COW  thread 0

  rax: 0x[PII_REDACTED]e5e1a0  rbx: 0x[PII_REDACTED]000006  rcx: 0x[PII_REDACTED]000100
 rdx: 0x[PII_REDACTED]e5e1a0
  rdi: 0x[PII_REDACTED]45b6c0  rsi: 0x00007fff507776d0  rbp: 0x00007fff525d5f30
 rsp: 0x00007fff507776d0
   r8: 0x[PII_REDACTED]000000   r9: 0x00007fff79e6a300  r10: 0x00007ff93c019790
 r11: 0x00007fff79147658
  r12: 0x[PII_REDACTED]00002d  r13: 0x00007fff507776d0  r14: 0x00007fff525d5880
 r15: 0x00007ff93ae41680
  rip: 0x00007fff901083c3  rfl: 0x[PII_REDACTED]010202  cr2: 0x00007fff507776c8