Flashback Malware Exploiting Unpatched Java on Macs [Updated]
There’s a piece of Mac malware, known as ‘Flashback’, that’s going around and takes advantage of a Java vulnerability in order to compromise and infect Macs online. Although the vulnerability isn’t Mac-specific, and was patched back in February, Apple has yet to distribute that update to everyone via Software Update, leaving everyone vulnerable.
Apparently the team behind this malware is quite efficient at updating it, and so they have been successful in spreading it around. Lion doesn’t come with Java by default, so unless you’ve manually installed it, you’re safe. If you have installed Java on Lion however, I don’t know yet whether Lion’s built-in anti-malware is being updated quickly enough to keep up with the new malware variants (although I highly doubt it).
If you are running Snow Leopard (or earlier), or Lion with a manually-installed Java, then the best thing to do is disable it. The majority of web users do not need Java on a regular basis. I recommend disabling Java system-wide by going to Applications > Utilities > Java Preferences and then unchecking all the checkboxes in the General tab. If you use Safari to browse, you can disable Java by going to Safari > Preferences > Security and unchecking ‘Enable Java‘.
Keep an eye out for an upcoming Java update from Apple.
[Updated] Seems all the talk about this has nudged Apple to act! They’ve released Java for OS X Lion 2012-001 and Java for Mac OS X 10.6 Update 7. F-Secure have released a free Flashback remover tool, and Apple have announced they are also working on software to detect and remove Flashback malware.
Source: F-Secure
Key iOS Security Updates Patch PDF and Certificate Validation Vulnerabilities (4.3.4 and 4.3.5)
The two latest iOS updates are fairly significant in that they patch two critical vulnerabilities. iOS update 4.3.4 patched a number of bugs including comex’s PDF/FreeType vulnerability used to create the latest JailbreakMe exploit. If you’re a jailbreaker, it’s essential that you run comex’s ‘PDF Patcher 2’ within Cydia, in order to patch the underlying vulnerability. iOS update 4.3.5 released a couple days ago, patches a fairly significant bug in the way iOS validates SSL/TLS certificates. This vulnerability can allow an attacker to intercept and/or modify data protected within an SSL session without the user knowing it. This was possible to due the fact that iOS didn’t validate the basicContstrains parameter of SSL certificates in the chain.
If you’re only an occasional patcher – now is the time.
Jailbreak iOS 4.3.3 with JailbreakMe 3.0
JailbreakMe.com has been updated to allow easy untethered jailbreak of your iOS devices, just follow the instructions on the site. Thanks to a new PDF exploit from comex (with the help of chpwn), it is now possible to jailbreak iPhones, iPads (including iPad 2) and iPod Touches running iOS 4.3.3 (note this doesn’t yet include any versions below that). During the jailbreak, saurik’s Cydia app store is automatically installed.
Interestingly, users with jailbroken devices can protect themselves by patching the PDF vulnerability by using ‘PDF Patcher 2’ in Cydia. Normal users will have to wait for iOS 4.3.4 from Apple. Note, however, that having a jailbroken iPhone or iPad still makes you slightly more vulnerable to other attacks, as the iOS sandbox is essentially bypassed.
Mac OS X Skype 0day Remote Code Execution Vulnerability [Updated]
A fairly significant 0day vulnerability is being reported in the Skype client (< 5.1.0.922) for Mac OS X. By sending a specially-crafted instant message, an attacker may be able to remotely execute code on the recipient’s computer and gain access to a root shell. This issue has been discovered (by accident it seems) by Gordon Maddern of Australian security consultancy Pure Hacking.
“About a month ago I was chatting on skype to a collegue about a payload for one of our clients. Completely by accident, my payload executed in my collegues skype client. I decided to investigate a little further and found that the Windows and Linux clients were not vulnerable. It was only the Mac skype client that seemed to be affected. […] Low and behold (sic) I was able to remotely gain a shell.”
It is believed that due to the relative simplicity in the delivery of the payload, it may be possible for this attack to be automated in the form of a worm. Skype are aware of this issue, but have yet to release a patch (see below). Mac users should be extra careful until a patch is made available, and in the short term I recommend quitting Skype when not using it, or at least checking that your Skype client is set to only allow messages from your contacts (Skype > Preferences > Privacy Tab > Allow Messages From: Contacts).
No further details or proof-of-concept of the vulnerability are available as of yet, although I’d be interested to see it… time to start pasting random Metasploit payloads into Skype! ;)
[Updated 8/5/2011] Skype addressed this vulnerability in version 5.1.0.922 of the Mac OS X client. Run the updater by going to the Skype menu > Check for Updates, or download the latest version here.
Full disclosure of the vulnerability is now available here. In short, the issue was a persistent XSS that could be used to redirect the user to a malicious website. Here’s the PoC attack string:
http://www.example.com/?foo=”><script>document.location=’http://10.11.1.225′;</script>
Safari Errorjacking Vulnerability and Exploit [Patched]
One of the vulnerabilities patched in Safari 5.0.4 is a fairly critical issue in WebKit (CVE-2011-0167) that allows Javascript to jump into the local zone, and access any file on the local computer that is accessible to the current user. This could be used by malicious websites to extract files and information from the victim’s computer. The vulnerability affects Safari on Mac OS X and Windows, and could affect other WebKit-based browsers, although Chrome is safe due to added restrictions.
The bug exists because most browser error pages are loaded from the local “file:” zone, a zone that Javascript is not normally allowed to access directly. Since a child browser window remains under the control of the parent, it is possible to cause a child browser window to error, thus entering the normally-restricted local zone, and then instructing the child window to access local files using this elevated local-zone privilege.
This issue was a nice catch, discovered by Aaron Sigel who has a detailed explanation, video demo and proof-of-concept on his blog. It probably goes without saying, but Safari users should run Software Update as soon as possible.
ProFTPD 1.3.3c Briefly Backdoored by Hackers
Servers of the widely popular FTP server, ProFTPD, were compromised (probably with 0day) on the 28th of November 2010. During the attack, some source code was modified to insert a backdoor. The source files affected were for ProFTPD version 1.3.3c., between the 28/11/2010 and 02/12/2010.
The backdoor introduced by the attackers allows unauthenticated users remote root access to systems which run the maliciously modified version of the ProFTPD daemon.
If you installed or updated ProFTPD from one of the official mirrors during that time, it is recommended that you recompile from a known good version of the code. The source modification was spotted and rectified on 01/12/2010. MD5 sums for the valid source tarballs:
8571bd78874b557e98480ed48e2df1d2 proftpd-1.3.3c.tar.bz2
4f2c554d6273b8145095837913ba9e5d proftpd-1.3.3c.tar.gz
Hit the jump for details on how the backdoor is triggered. A Metasploit module is available to automate the exploit. Read more
Chronic dev team releases greenpois0n jailbreak
The chronic dev team (@chronicdevteam) have released greenpois0n, their iOS jailbreak tool featuring an implementation of geohot’s bootrom exploit. Downloads are available for Mac OS X, Windows and Linux. It also only works on iOS 4.1.
This release of greenpois0n supports:
– iPhone 4
– iPhone 3G S
– iPod touch (4th Generation)
– iPod touch (3rd Generation)
– iPad
Soon there will be another release, adding things like support for:
– Apple TV (2nd Generation)
– iPod touch (2nd Generation)
[Updated 4/2/2011] greenpois0n updated to jailbreak iOS 4.2.1
Apple QuickTime 7.6.7 “_Marshaled_pUnk” Code Execution Vulnerability and Metasploit Exploit
A new (read: yet another) 0day QuickTime vulnerability has been discovered by researcher Ruben Santamarta which leads to arbitrary client-side code execution. The vulnerability, which affects QuickTime <= 7.6.7 on Windows XP, Vista and 7 and defeats DEP and ASLR, is due to a flaw in the way the QuickTime ActiveX controller handles a supplied parameter and treats it as a trusted pointer.
This vulnerability can be exploited by luring the victim to a malicious web page. A heap-spraying Metasploit module has already been published which exploits this issue.
September: Month of Abysssec Undisclosed Bugs (MOAUB)
Security research group Abysssec have announced the start of the Month of Abusssec Undisclosed Bugs (MOAUB) on the 1st of September. Unlike previous similar month-long vulnerability releases which tended to be themed, such as MOAB (Apple bugs) and MOPB (PHP bugs), Abysssec will be releasing advisories for a number of vendors including Microsoft, Mozilla, Sun, Apple, Adobe, HP, Novel, and several others. Some advisories will include proof-of-concepts and exploits.
The MOAUB will be hosted at the Exploit-DB, and it’ll be interesting to see how good the bugs will be.
Drop back here for my analysis of the more interesting vulns (including any Apple bugs).
QuickTime Player SMIL Buffer Overflow and Metasploit Exploit
On the 26th July 2010, Krystian Kloskowski discovered a vulnerability in QuickTime Player 7.6.6 for Windows caused by a buffer overflow in the application’s error logging.
The original advisory states:
The vulnerability is caused due to a boundary error in QuickTimeStreaming.qtx when constructing a string to write to a debug log file. This can be exploited to cause a stack-based buffer overflow by e.g. tricking a user into viewing a specially crafted web page that references a SMIL file containing an overly long URL.
Successful exploitation of this vulnerability leads to the ability of executing arbitrary code on the victim’s computer.
A couple of days ago, Joshua Drake (aka. jduck) submitted a working exploit module to the Metasploit Framework.
As QuickTime is installed on many Windows systems these days (it’s included as part of iTunes), this vulnerability poses a real threat. As always users should beware of clicking on unknown links, but ultimately if someone wants to get you to visit a malicious page, they can.
In this case users should update QuickTime asap. Apple has released QuickTime 7.6.7 which fixes this issue.
[Update] Check out the video below for a demo of the Metasploit module in action:
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