Security
BrowserID: A new web authentication scheme
Identity and authentication on the internet is still an unsolved problem. Some sites are delegating the problem to Facebook, Twitter, and others, but that has obvious privacy and control problems, which makes it worrisome for at least some users. OpenID has never really gained much traction, and alternate user-centric proposals, like the related OpenID Connect, haven't either. There are both technical and "social" barriers that haven't been overcome. Mozilla's recent BrowserID proposal looks toward solving a subset of the identity problem by making it easier for users to log in to web applications without having to remember (or duplicate) multiple usernames and passwords.
One of the main differences between BrowserID and the other solutions is that it decouples the identity question from that of authentication. Essentially, using the Verified Email Protocol (VEP) that underlies BrowserID will simply authenticate that a given email address corresponds to the browser that is being used to sign in. OpenID and others supplement that authentication with the idea of a verified identity that could include things like email address, real name, physical address, photo, and so on. BrowserID and VEP forgo all of that, which may or may not make it more palatable to web site operators.
For users who control their own email domain, or whose email provider implements the protocol, VEP's operation is fairly straightforward. The email provider acts as an "authority" to authenticate its email addresses. A user who wants to have a verified email address would authenticate with the authority (via a username/password in web mail application for example) and the authority would make a JavaScript call that tells the browser that the authentication was successful. That call would then generate a public/private key pair, sending the public key to the authority and storing the private key locally. A user could have multiple identities, each tied to a unique email, at one or more authorities.
When the user logs into a site that allows VEP authentication (i.e. a "relying party" or RP), they would be prompted to choose one of their email addresses to use. The browser would then create an "assertion" that listed the email address, a timestamp, and some other information, sign it with the private key, and send it to the site. The site then contacts the authority to get the public key for the user and verifies that the assertion is correctly signed. At that point, the web site can be sure that it is talking to a browser that is (or was at one point) controlled by a user with that email address.
Obviously, email providers are not likely to be falling all over themselves to implement an in-progress protocol, and it may be years—if ever—before they do, so VEP has the concept of "secondary verifiers" that would be stand-ins for the email provider authorities. If the user trusted the secondary (to respect their privacy for example), they could establish their control of a particular email address via a link in an email sent by the secondary. That would include the browser in the transaction so that the key pair could be generated and the public key sent to the secondary. If an RP also trusted the secondary, it could retrieve the public key from there and verify the authenticity of the email-browser connection that way.
In addition, some smaller web sites might wish (or need) to farm out the
verification to a verification service run by a trusted third party. As the
VEP wiki page notes: "These services obviously have tremendous power
and would need to be constructed with both technical and legal
care.
"
Doing a round-trip SSL transaction to an authority (or secondary verifier) whenever a user logs in may add unacceptable latency to the log in process. It would also leak information about which sites a user is visiting to the authority. One way to handle that is with an "identity certificate" that contains the user's public key and is signed by the authority. That way, a web site would only be retrieving the authority's public key, not the user's, and that authority key could be cached by the site to eliminate all but one of the retrieval round-trips. But that raises the problem of key revocation.
VEP is certainly not alone in having that particular problem. To a certain extent, all public key encryption mechanisms suffer from key revocation problems. In fact, key management is one of the hardest problems to solve for public key cryptography. As the VEP page notes, there are already problems with revocation for SSL certificates:
Much of the actual guts of the protocol are still being worked out, and it is interesting to see that some flexibility in the protocol is envisioned. The wiki document describes it this way:
Specifically: The explanation contained here will assume that user data lookups occur through the Webfinger protocol, that site-level metadata is retrieved through HTTPS using the .well-known/host-meta mechanism described in IETF RFC 5785 and draft-hammer-hostmeta, that assertions are generated and signed according to the JSON Web Tokens draft, and that asymmetric cryptography is performed using either RSA or ECDSA keypairs. When reference to a public key certificate is made, it is usually assumed that this would be an X509 certificate but there is no strong requirement that it be.
There are, of course, some concerns about BrowserID, not least the fact that an enormous amount of sensitive information would be stored by the browser (i.e. any public keys the user has generated) on a user's computer or device. In some ways, though, that's not much different than the current practice of storing username/password pairs for multiple web sites. Protecting that data store is clearly of utmost importance (whether BrowserID ever takes off or not).
BrowserID itself is a JavaScript implementation of VEP that will run in
"all modern browsers, including recent versions of IE, and on mobile
browsers
" according to the Mozilla announcement. In addition to
that and the VEP documents, Mozilla has set up
browserid.org as the central location
for information about the protocol and implementation.
Mozilla would clearly like to see other browser makers, users, and web sites work with it to firm up BrowserID and see it headed in a direction toward deployment. It's unclear whether that will happen or whether BrowserID will be yet another failed identity experiment. It certainly does have some interesting properties, and would allow sites to gather the extra information from users that they crave (i.e. beyond just an email address). When a user sets up an account, the application could request or require much more than just the email address it needs for authentication. The lack of that extra information is part of the reason that OpenID has never really taken off (and why OpenID Connect was proposed). One thing seems sure, solutions to this problem (or related set of problems) will keep coming up until something that is easy to use and can cater to privacy-conscious users actually becomes widespread.
Brief items
Security quotes of the week
From there, he could make a few small changes to the firmware, but not what he really wanted. So he poked around a bit more and found that a second password was required to move the battery into full access mode, which gave him the ability to make any changes he wished. That password is a default set at the factory and it's not changed on laptops before they're shipped. Once he had that, Miller found he could do a lot of interesting things with the battery.
Stage 2 (finding): All players registered are given a bundle with the different pieces of source code. To each bundle the organizers will add a few placebos (source codes that fulfill the requirements but should not include a backdoor). Before a deadline, the players must answer for each source code if they believe it includes a backdoor or not.
Embedded Web Servers Exposing Organizations To Attack (Dark Reading)
Dark Reading previews another talk from the upcoming Black Hat conference, this time on embedded web servers that have been connected to the internet, probably unknowingly. "[Michael] Sutton used Amazon EC2 computing resources to constantly scan large blocks of addresses and to detect any embedded Web servers. Sharp and Ricoh copiers digitally archive past photocopies, he notes, so if that feature is enabled and the copier is sitting on the Net unsecured, an attacker could retrieve any previously photocopied documents, he says. Even the fax-forwarding feature in some HP scanners could be abused if the scanner were open to the Internet: An attacker could access any faxed documents to the user by having them forwarded to his fax machine, for example."
New vulnerabilities
cifs-utils: /etc/mtab file corruption
| Package(s): | cifs-utils | CVE #(s): | CVE-2011-1678 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | July 25, 2011 | Updated: | September 23, 2011 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the CVE entry:
smbfs in Samba 3.5.8 and earlier attempts to use (1) mount.cifs to append to the /etc/mtab file and (2) umount.cifs to append to the /etc/mtab.tmp file without first checking whether resource limits would interfere, which allows local users to trigger corruption of the /etc/mtab file via a process with a small RLIMIT_FSIZE value, a related issue to CVE-2011-1089. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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freetype: arbitrary code execution
| Package(s): | freetype | CVE #(s): | CVE-2011-0226 | ||||||||||||||||||||||||||||||||||||||||
| Created: | July 21, 2011 | Updated: | August 31, 2011 | ||||||||||||||||||||||||||||||||||||||||
| Description: | From the CVE entry:
Integer signedness error in psaux/t1decode.c in FreeType before 2.4.6, as used in CoreGraphics in Apple iOS before 4.2.9 and 4.3.x before 4.3.4 and other products, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted Type 1 font in a PDF document, as exploited in the wild in July 2011. | ||||||||||||||||||||||||||||||||||||||||||
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icedtea-web: multiple vulnerabilities
| Package(s): | icedtea-web | CVE #(s): | CVE-2011-2513 CVE-2011-2514 | ||||||||||||||||||||||||
| Created: | July 25, 2011 | Updated: | August 2, 2011 | ||||||||||||||||||||||||
| Description: | From the Red Hat bugzilla: [1, 2]
Omair Majid discovered an information disclosure flaw in the JNLP (Java Network Launching Protocol) implementation used in IcedTea and IcedTea-web. An unsigned Java Web Start application or Java Applet could use this flaw to determine a path to the cache directory (/home/<username>/.netx/cache/) used to store downloaded jars for Web Start application or Applet by querying class's ClassLoader properties. This discloses full path to user's home directory on the local system and user's login name. Omair Majid discovered a flaw in the JNLP (Java Network Launching Protocol) implementation used in IcedTea-web. An unsigned Java Web Start application could use this flaw to manipulate content of the Security Warning dialog to show different file name than the one access to which was requested by the applications. This could confuse user to grant unintended access to local files. | ||||||||||||||||||||||||||
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kernel: denial of service
| Package(s): | kernel | CVE #(s): | CVE-2011-1780 CVE-2011-2525 CVE-2011-2689 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | July 21, 2011 | Updated: | November 21, 2011 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the Red Hat advisory:
* A flaw was found in the way the Xen hypervisor implementation handled instruction emulation during virtual machine exits. A malicious user-space process running in an SMP guest could trick the emulator into reading a different instruction than the one that caused the virtual machine to exit. An unprivileged guest user could trigger this flaw to crash the host. This only affects systems with both an AMD x86 processor and the AMD Virtualization (AMD-V) extensions enabled. (CVE-2011-1780, Important) * A flaw allowed the tc_fill_qdisc() function in the Linux kernel's packet scheduler API implementation to be called on built-in qdisc structures. A local, unprivileged user could use this flaw to trigger a NULL pointer dereference, resulting in a denial of service. (CVE-2011-2525, Moderate) * A flaw was found in the way space was allocated in the Linux kernel's Global File System 2 (GFS2) implementation. If the file system was almost full, and a local, unprivileged user made an fallocate() request, it could result in a denial of service. Note: Setting quotas to prevent users from using all available disk space would prevent exploitation of this flaw. (CVE-2011-2689, Moderate) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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kernel: multiple vulnerabilities
| Package(s): | kernel | CVE #(s): | CVE-2011-1020 CVE-2011-2183 CVE-2011-2491 CVE-2011-2496 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | July 25, 2011 | Updated: | December 27, 2011 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the SUSE advisory:
CVE-2011-1020: The proc filesystem implementation in the Linux kernel did not restrict access to the /proc directory tree of a process after this process performs an exec of a setuid program, which allowed local users to obtain sensitive information or cause a denial of service via open, lseek, read, and write system calls. CVE-2011-2183: Fixed a race between ksmd and other memory management code, which could result in a NULL ptr dereference and kernel crash. CVE-2011-2491: A local unprivileged user able to access a NFS filesystem could use file locking to deadlock parts of an nfs server under some circumstance. CVE-2011-2496: The normal mmap paths all avoid creating a mapping where the pgoff inside the mapping could wrap around due to overflow. However, an expanding mremap() can take such a non-wrapping mapping and make it bigger and cause a wrapping condition. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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libsndfile: arbitrary code execution
| Package(s): | libsndfile | CVE #(s): | CVE-2011-2696 | ||||||||||||||||||||||||||||||||||||||||||||
| Created: | July 21, 2011 | Updated: | December 18, 2013 | ||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the Red Hat advisory:
An integer overflow flaw, leading to a heap-based buffer overflow, was found in the way the libsndfile library processed certain Ensoniq PARIS Audio Format (PAF) audio files. An attacker could create a specially-crafted PAF file that, when opened, could cause an application using libsndfile to crash or, potentially, execute arbitrary code with the privileges of the user running the application. | ||||||||||||||||||||||||||||||||||||||||||||||
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logrotate: symlink and hard link attacks
| Package(s): | logrotate | CVE #(s): | CVE-2011-1548 | ||||
| Created: | July 21, 2011 | Updated: | July 27, 2011 | ||||
| Description: | From the CVE entry:
The default configuration of logrotate on Debian GNU/Linux uses root privileges to process files in directories that permit non-root write access, which allows local users to conduct symlink and hard link attacks by leveraging logrotate's lack of support for untrusted directories, as demonstrated by /var/log/postgresql/. | ||||||
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mapserver: multiple vulnerabilities
| Package(s): | mapserver | CVE #(s): | CVE-2011-2703 CVE-2011-2704 | ||||||||
| Created: | July 26, 2011 | Updated: | October 30, 2012 | ||||||||
| Description: | From the Debian advisory:
CVE-2011-2703: Several instances of insufficient escaping of user input, leading to SQL injection attacks via OGC filter encoding (in WMS, WFS, and SOS filters). CVE-2011-2704: Missing length checks in the processing of OGC filter encoding that can lead to stack-based buffer overflows and the execution of arbitrary code. | ||||||||||
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opensaml2: XML signature wrapping attack
| Package(s): | opensaml2 | CVE #(s): | CVE-2011-1411 | ||||||||
| Created: | July 25, 2011 | Updated: | September 27, 2011 | ||||||||
| Description: | From the Debian advisory:
Juraj Somorovsky, Andreas Mayer, Meiko Jensen, Florian Kohlar, Marco Kampmann and Joerg Schwenk discovered that Shibboleth, a federated web single sign-on system is vulnerable to XML signature wrapping attacks. More details can be found in the Shibboleth advisory at http://shibboleth.internet2.edu/security-advisories.html. | ||||||||||
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opie: privilege escalation/code execution
| Package(s): | opie | CVE #(s): | CVE-2011-2489 CVE-2011-2490 | ||||||||
| Created: | July 21, 2011 | Updated: | July 27, 2011 | ||||||||
| Description: | From the Debian advisory:
Sebastian Krahmer discovered that opie, a system that makes it simple to use One-Time passwords in applications, is prone to a privilege escalation (CVE-2011-2490) and an off-by-one error, which can lead to the execution of arbitrary code (CVE-2011-2489). | ||||||||||
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phpmyadmin: multiple vulnerabilities
| Package(s): | phpmyadmin | CVE #(s): | CVE-2011-2505 CVE-2011-2506 CVE-2011-2507 CVE-2011-2508 CVE-2011-2642 | ||||||||||||||||||||
| Created: | July 27, 2011 | Updated: | August 15, 2011 | ||||||||||||||||||||
| Description: | From the Debian advisory:
CVE-2011-2505: Possible session manipulation in Swekey authentication. CVE-2011-2506: Possible code injection in setup script, in case session variables are compromised. CVE-2011-2507: Regular expression quoting issue in Synchronize code. CVE-2011-2508: Possible directory traversal in MIME-type transformation. CVE-2011-2642: Cross site scripting in table Print view when the attacker can create crafted table names. | ||||||||||||||||||||||
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qemu-kvm: privilege escalation
| Package(s): | qemu-kvm | CVE #(s): | CVE-2011-2527 | ||||||||||||||||||||||||||||
| Created: | July 25, 2011 | Updated: | August 20, 2012 | ||||||||||||||||||||||||||||
| Description: | From the Debian advisory:
Andrew Griffiths discovered that group privileges were insufficiently dropped when started with -runas option, resulting in privilege escalation. | ||||||||||||||||||||||||||||||
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rgmanager: privilege escalation
| Package(s): | rgmanager | CVE #(s): | CVE-2010-3389 | ||||||||||||||||||||||||||||
| Created: | July 21, 2011 | Updated: | December 9, 2011 | ||||||||||||||||||||||||||||
| Description: | From the Red Hat advisory:
The rgmanager package contains the Red Hat Resource Group Manager, which provides the ability to create and manage high-availability server applications in the event of system downtime. It was discovered that certain resource agent scripts set the LD_LIBRARY_PATH environment variable to an insecure value containing empty path elements. A local user able to trick a user running those scripts to run them while working from an attacker-writable directory could use this flaw to escalate their privileges via a specially-crafted dynamic library. | ||||||||||||||||||||||||||||||
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ruby: predictable random numbers
| Package(s): | ruby | CVE #(s): | CVE-2011-2686 CVE-2011-2705 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | July 26, 2011 | Updated: | January 31, 2012 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the Red Hat bugzilla:
It was found that Ruby did not properly reinitialize the random number generator, when forking new Ruby process. A local attacker could use this flaw to easier predict random numbers. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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samba: multiple vulnerabilities
| Package(s): | samba | CVE #(s): | CVE-2011-2522 CVE-2011-2694 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | July 27, 2011 | Updated: | September 23, 2011 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the Mandriva advisory:
All current released versions of Samba are vulnerable to a cross-site request forgery in the Samba Web Administration Tool (SWAT). By tricking a user who is authenticated with SWAT into clicking a manipulated URL on a different web page, it is possible to manipulate SWAT (CVE-2011-2522). All current released versions of Samba are vulnerable to a cross-site scripting issue in the Samba Web Administration Tool (SWAT). On the Change Password field, it is possible to insert arbitrary content into the user field (CVE-2011-2694). | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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squirrelmail: multiple vulnerabilities
| Package(s): | squirrelmail | CVE #(s): | CVE-2011-2023 CVE-2010-4555 CVE-2010-4554 | ||||||||||||||||||||||||||||||||||||||||
| Created: | July 25, 2011 | Updated: | August 15, 2011 | ||||||||||||||||||||||||||||||||||||||||
| Description: | From the CVE entries:
Cross-site scripting (XSS) vulnerability in functions/mime.php in SquirrelMail before 1.4.22 allows remote attackers to inject arbitrary web script or HTML via a crafted STYLE element in an e-mail message. (CVE-2011-2023) Multiple cross-site scripting (XSS) vulnerabilities in SquirrelMail 1.4.21 and earlier allow remote attackers to inject arbitrary web script or HTML via vectors involving (1) drop-down selection lists, (2) the > (greater than) character in the SquirrelSpell spellchecking plugin, and (3) errors associated with the Index Order (aka options_order) page. (CVE-2010-4555) functions/page_header.php in SquirrelMail 1.4.21 and earlier does not prevent page rendering inside a frame in a third-party HTML document, which makes it easier for remote attackers to conduct clickjacking attacks via a crafted web site. (CVE-2010-4554) | ||||||||||||||||||||||||||||||||||||||||||
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systemtap: privilege escalation
| Package(s): | systemtap | CVE #(s): | CVE-2011-2502 CVE-2011-2503 | ||||||||||||||||||||||||||||||||
| Created: | July 26, 2011 | Updated: | September 23, 2011 | ||||||||||||||||||||||||||||||||
| Description: | From the Red Hat advisory:
It was found that SystemTap did not perform proper module path sanity checking if a user specified a custom path to the uprobes module, used when performing user-space probing ("staprun -u"). A local user who is a member of the stapusr group could use this flaw to bypass intended module-loading restrictions, allowing them to escalate their privileges by loading an arbitrary, unsigned module. (CVE-2011-2502) A race condition flaw was found in the way the staprun utility performed module loading. A local user who is a member of the stapusr group could use this flaw to modify a signed module while it is being loaded, allowing them to escalate their privileges. (CVE-2011-2503) | ||||||||||||||||||||||||||||||||||
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wireshark: denial of service
| Package(s): | wireshark | CVE #(s): | CVE-2011-2597 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | July 25, 2011 | Updated: | August 10, 2011 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the CVE entry:
The Lucent/Ascend file parser in Wireshark 1.2.x before 1.2.18, 1.4.x through 1.4.7, and 1.6.0 allows remote attackers to cause a denial of service (infinite loop) via malformed packets. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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