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A Month Without Adobe Flash Player

mardi 23 juin 2015 à 14:35

I’ve spent the better part of the last month running a little experiment to see how much I would miss Adobe‘s buggy and insecure Flash Player software if I removed it from my systems altogether. Turns out, not so much.

brokenflash-aBrowser plugins are favorite targets for malware and miscreants because they are generally full of unpatched or undocumented security holes that cybercrooks can use to seize complete control over vulnerable systems. The Flash Player plugin is a stellar example of this: It is among the most widely used browser plugins, and it requires monthly patching (if not more frequently).

It’s also not uncommon for Adobe to release emergency fixes for the software to patch flaws that bad guys started exploiting before Adobe even knew about the bugs. This happened most recently in February 2015, and twice the month prior. Adobe also shipped out-of-band Flash fixes in December and November 2014.

Update, 11:30 a.m. ET: Oddly enough, Adobe just minutes ago released an out-of-band patch to fix a zero-day flaw in Flash.

Original story:

Time was, Oracle’s Java plugin was the favorite target of exploit kits, software tools made to be stitched into hacked or malicious sites and foist on visiting browsers a kitchen sink of exploits for various plugin vulnerabilities. Lately, however, it seems to pendulum has swung back in favor of exploits for Flash Player. A popular exploit kit known as Angler, for example, bundled a new exploit for a Flash vulnerability just three days after Adobe fixed it in April 2015.

So, rather than continue the patch madness and keep this insecure software installed, I decided to the pull the…er…plugin. I tend to (ab)use different browsers for different tasks, and so uninstalling the plugin was almost as simple as uninstalling Flash, except with Chrome, which bundles its own version of Flash Player. Fear not: disabling Flash in Chrome is simple enough. On a Windows, Mac, Linux or Chrome OS installation of Chrome, type “chrome:plugins” into the address bar, and on the Plug-ins page look for the “Flash” listing: To disable Flash, click the disable link (to re-enable it, click “enable”).

In almost 30 days, I only ran into just two instances where I encountered a site hosting a video that I absolutely needed to watch and that required Flash (an instructional video for a home gym that I could find nowhere else, and a live-streamed legislative hearing). For these, I opted to cheat and load the content into a Flash-enabled browser inside of a Linux virtual machine I have running inside of VirtualBox. In hindsight, it probably would have been easier simply to temporarily re-enable Flash in Chrome, and then disable it again until the need arose.

If you decide that removing Flash altogether or disabling it until needed is impractical, there are in-between solutions. Script-blocking applications like Noscript and ScriptSafe are useful in blocking Flash content, but script blockers can be challenging for many users to handle.

Another approach is click-to-play, which is a feature available for most browsers (except IE, sadly) that blocks Flash content from loading by default, replacing the content on Web sites with a blank box. With click-to-play, users who wish to view the blocked content need only click the boxes to enable Flash content inside of them (click-to-play also blocks Java applets from loading by default).

Windows users who decide to keep Flash installed and/or enabled also should take full advantage of the Enhanced Mitigation Experience Toolkit (EMET), a free tool from Microsoft that can help Windows users beef up the security of third-party applications.

“Free” Proxies Aren’t Necessarily Free

lundi 22 juin 2015 à 20:02

Netflix, Hulu and a host of other content streaming services block non-U.S. users from viewing their content. As a result, many people residing in or traveling outside of the United States seek to circumvent such restrictions by using services that advertise “free” and “open” Web proxies capable of routing browser traffic through U.S.-based computers and networks. Perhaps unsurprisingly, new research suggests that most of these “free” offerings are anything but, and actively seek to weaken browser security and privacy.

proxyThe data comes from Austrian researcher and teacher Christian Haschek, who published a simple script to check 443 open Web proxies (no, that number was not accidental). His script tries to see if a given proxy allows encrypted browser traffic (https://), and whether the proxy tries to modify site content or inject any content into the user’s browser session, such as ads or malicious scripts.

Haschek found that 79 percent of the proxies he tested forced users to load pages in unencrypted (http://) mode, meaning the owners of those proxies could see all of the traffic in plain text.

“It could be because they want you to use http so they can analyze your traffic and steal your logins,” Haschek said. “If I’m a good guy setting up a server so that people can use it to be secure and anonymous, I’m going to allow people to use https. But what is my motive if I tell users http only?”

Haschek’s research also revealed that slightly more than 16 percent of the proxy servers were actively modifying static HTML pages to inject ads.

Virtual private networks (VPNs) allow users to tunnel their encrypted traffic to different countries, but increasingly online content providers are blocking popular VPN services as well. Tor offers users the ability to encrypt and tunnel traffic for free, but in my experience the service isn’t reliably fast enough to stream video.

Haschek suggests that users who wish to take advantage of open proxies pick ones that allow https traffic. He’s created and posted online a free tool that allows anyone to test whether a given proxy permits encrypted Web traffic, as well as whether the proxy truly hides the user’s real Internet address. This blog post explains more about his research methodology and script.

Users who wish to take advantage of open proxies also should consider doing so using a Live CD or virtual machine setup that makes it easy to reset the system to a clean installation after each use. I rely on the free VirtualBox platform to run multiple virtual machines, a handful of which I use to do much of my regular browsing, tweeting, emailing and other things that can lead sometimes to malicious links, scripts, etc.

I’ll most likely revisit setting up your own VirtualBox installation in a future post, but this tutorial offers a fairly easy-to-follow primer on how to run a Live CD installation of a Linux distribution of your choosing on top of VirtualBox.

OPM’s Database for Sale? Nope, It Came from Another US .Gov

jeudi 18 juin 2015 à 14:12

A database supposedly from a sample of information stolen in the much publicized hack at the Office of Personnel Management (OPM) has been making the rounds in the cybercrime underground, with some ne’er-do-wells even offering to sell it as part of a larger package. But a review of the information made available as a teaser indicates that the database is instead a list of users stolen from a different government agency — Unicor.gov, also known as Federal Prison Industries.

Source: Unicor.gov

Source: Unicor.gov

Earlier this week, miscreants who frequent the Hell cybercrime forum (a “Deep Web” site reachable only via the Tor network) began passing around a text file that contained more than 23,000 records which appeared to be a user database populated exclusively by user accounts with dot-gov email addresses. I thought it rather unlikely that the file had anything to do with the OPM hack, which was widely attributed to Chinese hackers who are typically interested in espionage — not selling the data they steal on open-air markets.

As discussed in my Oct. 2014 post, How to Tell Data Leaks from Publicity Stunts, there are several simple techniques that often can be used to tell whether a given data set is what it claims to be. One method involves sampling email addresses from the leaked/hacked database and then using them in an attempt to create new accounts at the site in question. In most cases, online sites and services will allow only one account per email address, so if a large, random sampling of email addresses from the database all come back as already registered at the site you suspect is the breached entity, then it’s a safe guess the data came from that entity.

How to know the identity of the organization from which the database was stolen? In most cases, database files list the users in the order in which they registered on the site. As a result, the email addresses and/or usernames for the first half-dozen or more users listed in the database are most often from the database administrators and/or site designers. When all of those initial addresses have the same top-level domain — in this case “unicor.gov” — it’s a good bet that’s your victim organization.

Image: Unicor.gov

Image: Unicor.gov

According to Wikipedia, UNICOR is a wholly owned United States government corporation created in 1934 that uses penal labor from the Federal Bureau of Prisons to produce goods and services. It is apparently restricted to selling its products and services to federal government agencies, although recently private companies gained some access to UNICOR workforce. For instance, companies can outsource call centers to UNICOR. Case in point: If you call UNICOR’s main number off-hours, the voicemail message states that during business hours your call may be handled by an inmate!

On Tuesday, I reached out to UNICOR to let them know that it appeared their user database — including hashed passwords and other information — was being traded on underground cybercrime forums. On Wednesday, I heard back from Marianne Cantwell, the public information officer for UNICOR. Cantwell said a review of the information suggests it is related to an incident in September 2013, when Federal Prison Industries discovered unauthorized access to its public Web site.

“Since that time, the website software has been replaced to improve security. Assessments by proper law enforcement authorities were conducted to determine the extent of the incident, at the time it was discovered,” said Cantwell, who confirmed the incident hadn’t been previously disclosed publicly. “Limited individuals were deemed to be potentially impacted, and notifications were made as a precautionary measure. Federal Prison Industries is sensitive to ensuring the security of its systems and will continue to monitor this issue.”

The “website software” in question was ColdFusion, a Web application platform owned by Adobe Systems Inc. Around that same time, hackers were running around breaking into a number of government and corporate Web sites and databases using ColdFusion vulnerabilities. In October 2013, I wrote about criminals who had used ColdFusion exploits to break into and steal the database from the National White Collar Crime Center (NW3C), a congressionally-funded non-profit organization that provides training, investigative support and research to agencies and entities involved in the prevention, investigation and prosecution of cybercrime.

There is no information to link the hack at UNICOR to the crooks behind the NW3C compromise, but it’s interesting to note that those responsible for the NW3C attack also had control over the now-defunct identity theft service ssndob[dot]ms. That service, which was advertised on cybercrime forums, was powered in part by a small but powerful collection of hacked computers exclusively at top data brokers, including LexisNexis, Dun & Bradstreet, and HireRight/Kroll.

Critical Flaws in Apple, Samsung Devices

mercredi 17 juin 2015 à 19:15

Normally, I don’t cover vulnerabilities about which the user can do little or nothing to prevent, but two newly detailed flaws affecting hundreds of millions of Android, iOS and Apple products probably deserve special exceptions.

keychainThe first is a zero-day bug in iOS and OS X that allows the theft of both Keychain (Apple’s password management system) and app passwords. The flaw, first revealed in an academic paper (PDF) released by researchers from Indiana University, Peking University and the Georgia Institute of Technology, involves a vulnerability in Apple’s latest operating system versions that enable an app approved for download by the Apple Store to gain unauthorized access to other apps’ sensitive data.

“More specifically, we found that the inter-app interaction services, including the keychain…can be exploited…to steal such confidential information as the passwords for iCloud, email and bank, and the secret token of Evernote,” the researchers wrote.

The team said they tested their findings by circumventing the restrictive security checks of the Apple Store, and that their attack apps were approved by the App Store in January 2015. According to the researchers, more than 88 percent of apps were “completely exposed” to the attack.

News of the research was first reported by The Register, which said that Apple was initially notified in October 2014 and that in February 2015 the company asked researchers to hold off disclosure for six months.

“The team was able to raid banking credentials from Google Chrome on the latest Mac OS X 10.10.3, using a sandboxed app to steal the system’s keychain and secret iCloud tokens, and passwords from password vaults,” The Register wrote. “Google’s Chromium security team was more responsive and removed Keychain integration for Chrome noting that it could likely not be solved at the application level. AgileBits, owner of popular software 1Password, said it could not find a way to ward off the attacks or make the malware ‘work harder’ some four months after disclosure.”

A story at 9to5mac.com suggests the malware the researchers created to run their experiments can’t directly access existing keychain entries, but instead does so indirectly by forcing users to log in manually and then capturing those credentials in a newly-created entry.

“For now, the best advice would appear to be cautious in downloading apps from unknown developers – even from the iOS and Mac App Stores – and to be alert to any occasion where you are asked to login manually when that login is usually done by Keychain,” 9to5’s Ben Lovejoy writes.

SAMSUNG KEYBOARD FLAW

Separately, researchers at mobile security firm NowSecure disclosed they’d found a serious vulnerability in a third-party keyboard app that is pre-installed on more than 600 million Samsung mobile devices — including the recently released Galaxy S6 — that allows attackers to remotely access resources like GPS, camera and microphone, secretly install malicious apps, eavesdrop on incoming/outgoing messages or voice calls, and access pictures and text messages on vulnerable devices.

The vulnerability in this case resides with an app called Swift keyboard, which according to researcher Ryan Welton runs from a privileged account on Samsung devices. The flaw can be exploited if the attacker can control or compromise the network to which the device is connected, such as a wireless hotspot or local network.

“This means that the keyboard was signed with Samsung’s private signing key and runs in one of the most privileged contexts on the device, system user, which is a notch short of being root,” Welton wrote in a blog post about the flaw, which was first disclosed at Black Hat London on Tuesday, along the release of proof-of-concept code.

Welton said NowSecure alerted Samsung in November 2014, and that at the end of March Samsung reported a patch released to mobile carriers for Android 4.2 and newer, but requested an additional three months deferral for public disclosure. Google’s Android security team was alerted in December 2014.

“While Samsung began providing a patch to mobile network operators in early 2015, it is unknown if the carriers have provided the patch to the devices on their network,” Welton said. “In addition, it is difficult to determine how many mobile device users remain vulnerable, given the devices models and number of network operators globally.” NowSecure has released a list of Samsung devices indexed by carrier and their individual patch status.

Samsung issued a statement saying it takes emerging security threats very seriously.

“Samsung KNOX has the capability to update the security policy of the phones, over-the-air, to invalidate any potential vulnerabilities caused by this issue. The security policy updates will begin rolling out in a few days,” the company said. “In addition to the security policy update, we are also working with SwiftKey to address potential risks going forward.”

A spokesperson for Google said the company took steps to mitigate the issue with the release of Android 5.0 in November 2014.

“Although these are most accurately characterized as application level issues, back with Android 5.0, we took proactive measures to reduce the risk of the issues being exploited,” Google said in a statement emailed to KrebsOnSecurity. “For the longer term, we are also in the process of reaching out to developers to ensure they follow best practices for secure application development.”

SwiftKey released a statement emphasizing that the company only became aware of the problem this week, and that it does not affect its keyboard applications available on Google Play or Apple App Store. “We are doing everything we can to support our long-time partner Samsung in their efforts to resolve this important security issue,” SwiftKey said in a blog post.

Update: SwiftKey’s Jennifer Kutz suggests that it’s incorrect to use the phrase “pre-installed app” to describe the component that Samsung ships with its devices: “A pre-installed app is definitely different from how we work with Samsung, who licenses/white-labels our technology – or prediction engine – to power their devices’ default/stock keyboards,” Kutz said. “The keyboard is not branded as SwiftKey, and the functionality between our Google Play app, or pre-installed SwiftKey app, is different from what Samsung users have (in short, the official SwiftKey app has a much more robust feature set). The SwiftKey SDK powers the word predictions – it’s a core part of our technology but it is not our full app.”

Password Manager LastPass Warns of Breach

mardi 16 juin 2015 à 06:16

LastPass, a company that offers users a way to centrally manage all of their passwords online with a single master password, disclosed Monday that intruders had broken into its databases and made off with user email addresses and password reminders, among other data.

lastpassIn an alert posted to its blog, LastPass said the company has found no evidence that its encrypted user vault data was taken, nor that LastPass user accounts were accessed.

“The investigation has shown, however, that LastPass account email addresses, password reminders, server per user salts, and authentication hashes were compromised,” the company said. “We are confident that our encryption measures are sufficient to protect the vast majority of users. LastPass strengthens the authentication hash with a random salt and 100,000 rounds of server-side PBKDF2-SHA256, in addition to the rounds performed client-side. This additional strengthening makes it difficult to attack the stolen hashes with any significant speed.”

Parsing LastPass’s statement requires a basic understanding of the way that passwords are generally stored. Passwords are “hashed” by taking the plain text password and running it against a theoretically one-way mathematical algorithm that turns the user’s password into a string of gibberish numbers and letters that is supposed to be challenging to reverse. 

The weakness of this approach is that hashes by themselves are static, meaning that the password “123456,” for example, will always compute to the same password hash. To make matters worse, there are plenty of tools capable of very rapidly mapping these hashes to common dictionary words, names and phrases, which essentially negates the effectiveness of hashing. These days, computer hardware has gotten so cheap that attackers can easily and very cheaply build machines capable of computing tens of millions of possible password hashes per second for each corresponding username or email address.

But by adding a unique element, or “salt,” to each user password, database administrators can massively complicate things for attackers who may have stolen the user database and rely upon automated tools to crack user passwords.

“What a salt does it makes it hard to go after a lot of passwords at once as opposed to one users’ password, because every user requires a separate guess and that separate guess is going to take a considerable amount of time,” said Steve Bellovin, a professor in computer science at Columbia University . “With a salt, even if a bunch of users have the same password, like ‘123456,’ everyone would have a different hash.”

More concerning in this particular breach, Bellovin said, is that users’ password reminders also were stolen.

“I suspect that for a significant number of people, the password reminder — in addition to the user’s email address — is going to be useful for an attacker,” he said. “But password reminders are useful for targeted attacks, not massive attacks. That means that if your password reminder or hint is not particularly revealing to someone who doesn’t know you, it probably doesn’t matter much. Except in the case of targeted phishing attacks,” which might try to leverage data known about a specific target (such as a password hint) to trick the user into giving up the answer to their password reminder. 

So what’s the takeaway here? If you entrust all of your passwords to LastPass, now would be a terrific time to change your master password.