iOS (Vulner)ability

iOS (Vulner)abilitySubho Halder Co Founder AppKnox

./WhoAmI

Co Founder of AppKnox ( XYSec Labs )

Python Lover

Security Geeks

Found Security Bugs in Apple, Google, Skype, Webkit, Facebook, Microsoft, …..

Security is ……

http://xkcd.com/327/

NSLog [@“Agenda”];

Quick overview of iPhone iOS Platform.

iOS Security Structure

What is a Jailbreak?

iOS App (IN)Securities

Peek into a state-of-art Prison

iOS Hardware Architecture

Application Processor

Baseband

iOSUser interaction

Applications ...

NucleusOSRadio communication

iOS Hardware Architecture

Application Processor Baseband Processor

audio

display

power managment

camera

WIFI

BT

GSM

UART

I2S GPIO DMA

controls sim/net-lock !

Phew, Security Architecture

***[Sandboxing]***

NAND Flash

FTL: converts logical partition to NAND flash architecture

looks like BLOCK device

System Partition / (Read Only)

User Partition /private/var NAND

FTL

Block Device

/ (RO) (System Partition)

/private/var (RW) (User Partition)

***[Sandboxing]***

3rd Party lives only on User Partition

Apps run as mobile user

Kernel Signature checks executables in system-call execve()

%{ How did you Jailbreak it? }%NAND

FTL

Block Device

/ (RO) (System Partition)

/private/var (RW) (User Partition)

**Memory Protection

W^X Policy

Non Executable Stack or Heap

ASLR (Address Space Layout Randomisation)

%{ Did you forget about Return-Oriented-Program }%

Code Signing

Implemented inside Kernel

Kernel signature checks executables in systemcall execve()

Kernel stored on System Partition (kernelcache)

Kernel is signature checked before being loaded.

%{ Can still be by-passed :/ }%

Encryption @#%$#^% !

Everythong is encrypted

Hardware AES Engine

Keys derived from hardware keys GID-key UID-key

%{Possible to use Jailbreak tools e.g. Syringe to use the hardware engine}%

What is J@!lbr3@k ?

How your iPhone boots up?

signature check

signature check

signature check

signature check

Bootrom LLB (Low Level Bootloader)

iBoot Kernel Application

NOR NOR NAND NAND

Recovery Mode?

BootromLLB

(Low Level Bootloader)

iBoot

signature check

signature check

Kernel

Kernel

Ramdisk

DFU Mode !

Bootrom iBSS iBEC Kernel

Ramdisk

Bootrom LLB (Low Level Bootloader)

iBoot Kernel Application

minimal iBoot

Attacking the chain of trust!

signature check

BootromLLB

(Low Level Bootloader)

iBoot Kernel Application

signature check

signature check

signature check

signature check

attack here

(cannot be fixed)

attack here attack here attack here

System Software

Where do we go wrong?

Plists

Used by iPhone to store saved properties and data

XML

Binary (compressed XML) (depreciated)

The binary plists need converting, you can use:

plutil to convert to XML

Property List Editor (in XCode)

plists contain all kinds of juicy information. Check for:

Cookies, emails, usernames, passwords, sensitive application data, client side role identifiers, protocol handlers, etc.

B00M! :O

INSERT into `SQLite`

A lot of iOS applications sensitive data in SQLite3 databases on the device.

Sqlite3 does not have built-in support for encryption.

There are extensions (CEROD is one, sqlcipher is another) that support encryption, but the code is not publicly available, you need to license it. Apple has not, so the included version of sqlite3 does not support encrypted databases.

Still dangerous to store stuff client side.

To bypass: Cerod is as simple as looking for “cerod:passwd” or break pointing and pulling out of memory: sqlite3_open(":cerod:passwd:filename.db", &db);

)()()( Keychains )()()(

Keychain = Encrypted container for storing sensitive information

Smarter devs store passwords and sensitive data using the keychain.

Unfortunately with access to a phone and jailbreaking we can decrypt the keychain and dump the contents.

tail -f /var/logs/

iOS Logs lots of data, NSLog especially, They can be viewed after the fact in:

~/Library/Logs/CrashReporter/MobileDevice/<Device name>/private/var/log/system.log

Can be viewed in you mac “console” app under utilities

File Caching \m/\m/

If the application uses PDF, Excel, or other files it may be possible that these files may have been cached on the device.

These can be found at: ~/Library/Application Support/iPhone simulator/x.x.x/Applications/<application folder>/Documents/temp.pdf

$(`Keyboard Caching`)

Keystrokes for predictive spellcheck are stored in:

~/Library/Application Support/iPhone Simulator/x.x.x/Library/Keyboard/dynamic-text.dat

This issue is similar to autocomplete for web browsers.

Already disabled for password fields Should be disabled for any potentially sensitive fields (account numbers, SSN, etc, etc…)

Set UITextField property autocorrectionType = UITextAutocorrectionNo for mitigation.

Snapshot Caching

When in an application and the home button is pushed, the application stores a snapshot (screenshot) in the apps snapshot folder

~/Library/Application Support/iPhone Simulator/x.x.x/Applications/<application folder>/Library/Caches/Snapshots/

These persist until reboot. Hopefully you weren’t on a screen with any sensitive data!

Snapshot Caching

SQL Injection Client-Side

SQL injection is a problem on the client side too!

BAD:

NSString *sql = [NSString stringWithFormat:@"SELECT name FROM products WHERE id = '%@'", id]; const char *query = [sql UTF8String];

GOOD:

const char *sql = "SELECT name FROM products WHERE id = ?"; sqlite3_prepare_v2(database, sql, -1, &sql_statement, NULL); sqlite3_bind_text(&sql_statement, 1, id, -1, SQLITE_TRANSIENT);

XSS Client-Side

Can occur whenever user controlled Objective C variables populated in to WebView

stringByEvaluatingJavaScriptFromString NSString *javascript = [[NSString alloc] initWithFormat:@"var myvar=\"%@\";", username]; [mywebView stringByEvaluatingJavaScriptFromString:javascript];

Vulnerable Obj-C Methods

NSLog()

[NSString stringWithFormat:]

[NSString initWithFormat:]

[NSMutableString appendFormat:]

[NSAlert informativeTextWithFormat:]

[NSPredicate predicateWithFormat:]

[NSException format:]

NSRunAlertPanel

How can you get started?

https://www.owasp.org/index.php/OWASP_iGoat_Project

AppKnox - Cloud Based Security Automation Tool

Available for Android Coming soon for iOS

–Cicero

“There is no castle so strong that it cannot be overthrown”

Thank Youhttps://www.appknox.com

http://subho.me @sunnyrockzzs

subho.halder@gmail.com