Security
Transport-level encryption with Tcpcrypt
It has been said that the US National Security Agency (NSA) blocked the implementation of encryption in the TCP/IP protocol for the original ARPANET, because it wanted to be able to listen in on the traffic that crossed that early precursor to the internet. Since that time, we have been relegated to always sending clear-text packets via TCP/IP. Higher level application protocols (i.e. ssh, HTTPS, etc.) have enabled encryption for some traffic, but the vast majority of internet communication is still in the clear. The Tcpcrypt project is an attempt to change that, transparently, so that two conforming nodes can encrypt all of the data portion of any packets they exchange.
One of the key benefits that Tcpcrypt offers is transparency. That means that if both endpoints of a connection support it, the connection will be encrypted, but if one doesn't support Tcpcrypt, the other will gracefully fall back to standard clear-text TCP/IP. No applications are required to change, and no "new" protocols are required (beyond Tcpcrypt itself, of course) as applications will send and receive data just as they do today. But there is an additional benefit available for those applications that are willing to change: strong authentication.
Tcpcrypt has the concept of a "session ID" that is generated on both sides as part of the key exchange. This ID can be used in conjunction with a shared secret, like a password, to authenticate both ends of the communication. Because the client and server can exchange cryptographic hash values derived from the shared secret and session ID, they can be assured that each is talking over an encrypted channel to an endpoint that has the key (password). A "man in the middle" would not have access to the password and therefore can't spoof the exchange.
Even without any application changes for stronger authentication, Tcpcrypt would defend against passive man-in-the-middle attacks, like eavesdropping. Active attacks could still spoof responses that said Tcpcrypt was not supported, even if the other endpoint did support it, or even relay encrypted traffic. That would still be better than the usual situation today where a passive attacker can gather an enormous amount of clear-text traffic, especially from unencrypted or weakly encrypted wireless networks.
There is an Internet Engineering Task Force (IETF) draft available that describes how Tcpcrypt works by using two new TCP options. Those two options, CRYPT and MAC, will not be recognized by endpoints without Tcpcrypt support, and are therefore harmless. The CRYPT option is used to negotiate the use of Tcpcrypt and to exchange encryption keys, while the MAC option carries a hash value that can be used to verify the integrity of the packet data.
In addition to the IETF draft, the project has produced a paper, The case for ubiquitous transport-level encryption [PDF], that was presented at the 2010 USENIX Security conference. It gives a somewhat higher-level look at how Tcpcrypt integrates with TCP/IP, while providing a lot more information on the cryptographic and authentication algorithms. The slides [PDF] from the presentation are also instructive.
One of the basic premises that underlies Tcpcrypt is that computers have gotten "fast enough" to handle encrypting all internet traffic. Doing so at the transport level, rather than in application protocols (e.g. ssh), can make it transparent to applications. In addition, Tcpcrypt can work through NAT devices, which is something that another lower-layer encryption protocol, IPSec, cannot handle.
Because Tcpcrypt keys are short-lived, non-persistent public/private key pairs, it does not require the public key infrastructure (PKI) that other solutions, like HTTPS, need. That means that endpoints can communicate without getting certificates signed by centralized authorities. Of course the existing PKI certificates will work just fine on top of Tcpcrypt.
While computers may be "fast enough" to handle encryption on every packet, there is still the problem of asymmetry. Servers typically handle much more traffic than clients, so Tcpcrypt is designed to put the most difficult parts of the key negotiation and encryption onto the client side. The claim is that speeds of up to 25x that of HTTPS (i.e. SSL/TLS) can be achieved by Tcpcrypt. One wonders whether mobile devices are "fast enough", but that problem—if it even is one—is probably not one for that much longer.
Overall, Tcpcrypt is an intriguing idea. It certainly isn't a panacea for all of today's network ills, but that is no surprise. Unlike other proposals, Tcpcrypt can be incrementally deployed without requiring that we, somehow, restart the internet. Since it won't break existing devices, it can be developed and tested within the framework of the existing net. If for no other reason, that should give Tcpcrypt a leg up on other potential solutions.
Brief items
Security quotes of the week
New vulnerabilities
acroread: arbitrary code execution
| Package(s): | acroread | CVE #(s): | CVE-2010-2862 | ||||||||||||
| Created: | August 20, 2010 | Updated: | September 1, 2010 | ||||||||||||
| Description: | From the Red Hat advisory:
This update fixes a vulnerability in Adobe Reader. This vulnerability is detailed on the Adobe security page APSB10-17, listed in the References section. A specially-crafted PDF file could cause Adobe Reader to crash or, potentially, execute arbitrary code as the user running Adobe Reader when opened. | ||||||||||||||
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cacti: multiple vulnerabilities
| Package(s): | cacti | CVE #(s): | CVE-2010-1644 CVE-2010-1645 CVE-2010-2543 CVE-2010-2544 CVE-2010-2545 | ||||||||||||||||
| Created: | August 24, 2010 | Updated: | January 9, 2012 | ||||||||||||||||
| Description: | From the Mandriva advisory:
Multiple cross-site scripting (XSS) vulnerabilities in Cacti before 0.8.7f, allow remote attackers to inject arbitrary web script or HTML via the (1) hostname or (2) description parameter to host.php, or (3) the host_id parameter to data_sources.php (CVE-2010-1644). Cacti before 0.8.7f, allows remote authenticated administrators to execute arbitrary commands via shell metacharacters in (1) the FQDN field of a Device or (2) the Vertical Label field of a Graph Template (CVE-2010-1645). Cross-site scripting (XSS) vulnerability in include/top_graph_header.php in Cacti before 0.8.7g allows remote attackers to inject arbitrary web script or HTML via the graph_start parameter to graph.php. NOTE: this vulnerability exists because of an incorrect fix for CVE-2009-4032.2.b (CVE-2010-2543). Cross-site scripting (XSS) vulnerability in utilities.php in Cacti before 0.8.7g, allows remote attackers to inject arbitrary web script or HTML via the filter parameter (CVE-2010-2544). Multiple cross-site scripting (XSS) vulnerabilities in Cacti before 0.8.7g, allow remote attackers to inject arbitrary web script or HTML via (1) the name element in an XML template to templates_import.php; and allow remote authenticated administrators to inject arbitrary web script or HTML via vectors related to (2) cdef.php, (3) data_input.php, (4) data_queries.php, (5) data_sources.php, (6) data_templates.php, (7) gprint_presets.php, (8) graph.php, (9) graphs_new.php, (10) graphs.php, (11) graph_templates_inputs.php, (12) graph_templates_items.php, (13) graph_templates.php, (14) graph_view.php, (15) host.php, (16) host_templates.php, (17) lib/functions.php, (18) lib/html_form.php, (19) lib/html_form_template.php, (20) lib/html.php, (21) lib/html_tree.php, (22) lib/rrd.php, (23) rra.php, (24) tree.php, and (25) user_admin.php (CVE-2010-2545). | ||||||||||||||||||
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freeciv: arbitrary command execution
| Package(s): | freeciv | CVE #(s): | CVE-2010-2445 | ||||||||||||||||
| Created: | August 20, 2010 | Updated: | February 7, 2014 | ||||||||||||||||
| Description: | From the CVE entry:
freeciv 2.2 before 2.2.1 and 2.3 before 2.3.0 allows attackers to read arbitrary files or execute arbitrary commands via scenario that contains Lua functionality, related to the (1) os, (2) io, (3) package, (4) dofile, (5) loadfile, (6) loadlib, (7) module, and (8) require modules or functions. | ||||||||||||||||||
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kernel: multiple vulnerabilities
| Package(s): | linux-2.6 | CVE #(s): | CVE-2009-4895 CVE-2010-2803 CVE-2010-2959 CVE-2010-3015 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | August 20, 2010 | Updated: | March 3, 2011 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the Debian advisory:
Kyle Bader reported an issue in the tty subsystem that allows local users to create a denial of service (NULL pointer dereference). (CVE-2009-4895) Kees Cook reported an issue in the DRM (Direct Rendering Manager) subsystem. Local users with sufficient privileges (local X users or members of the 'video' group on a default Debian install) could acquire access to sensitive kernel memory. (CVE-2010-2803) Ben Hawkes discovered an issue in the AF_CAN socket family. An integer overflow condition may allow local users to obtain elevated privileges. (CVE-2010-2959) Toshiyuki Okajima reported an issue in the ext4 filesystem. Local users could trigger a denial of service (BUG assertion) by generating a specific set of filesystem operations. (CVE-2010-3015) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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kvm: denial of service
| Package(s): | kvm | CVE #(s): | CVE-2010-0431 CVE-2010-0435 CVE-2010-2784 | ||||||||||||||||||||||||||||||||||||
| Created: | August 20, 2010 | Updated: | March 3, 2011 | ||||||||||||||||||||||||||||||||||||
| Description: | From the Red Hat advisory:
It was found that QEMU-KVM on the host did not validate all pointers provided from a guest system's QXL graphics card driver. A privileged guest user could use this flaw to cause the host to dereference an invalid pointer, causing the guest to crash (denial of service) or, possibly, resulting in the privileged guest user escalating their privileges on the host. (CVE-2010-0431) A flaw was found in QEMU-KVM, allowing the guest some control over the index used to access the callback array during sub-page MMIO initialization. A privileged guest user could use this flaw to crash the guest (denial of service) or, possibly, escalate their privileges on the host. (CVE-2010-2784) A NULL pointer dereference flaw was found when the host system had a processor with the Intel VT-x extension enabled. A privileged guest user could use this flaw to trick the host into emulating a certain instruction, which could crash the host (denial of service). (CVE-2010-0435) | ||||||||||||||||||||||||||||||||||||||
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moin: cross-site scripting
| Package(s): | moin | CVE #(s): | CVE-2010-2969 CVE-2010-2970 | ||||||||
| Created: | August 25, 2010 | Updated: | October 19, 2012 | ||||||||
| Description: | Versions of the MoinMoin wiki system through 1.7.3 or prior to 1.9.3 suffer from multiple cross-site scripting vulnerabilities. | ||||||||||
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moodle: multiple vulnerabilities
| Package(s): | moodle | CVE #(s): | CVE-2010-2795 CVE-2010-2796 | ||||||||||||||||||||||||||||
| Created: | August 23, 2010 | Updated: | February 23, 2011 | ||||||||||||||||||||||||||||
| Description: | From the CVE entries:
phpCAS before 1.1.2 allows remote authenticated users to hijack sessions via a query string containing a crafted ticket value. (CVE-2010-2795) Cross-site scripting (XSS) vulnerability in phpCAS before 1.1.2, when proxy mode is enabled, allows remote attackers to inject arbitrary web script or HTML via a callback URL. (CVE-2010-2796) | ||||||||||||||||||||||||||||||
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mozilla: denial of service
| Package(s): | firefox, thunderbird, sunbird | CVE #(s): | CVE-2010-2755 | ||||||||||||||||
| Created: | August 20, 2010 | Updated: | January 19, 2011 | ||||||||||||||||
| Description: | From the CVE entry:
layout/generic/nsObjectFrame.cpp in Mozilla Firefox 3.6.7 does not properly free memory in the parameter array of a plugin instance, which allows remote attackers to cause a denial of service (memory corruption) or possibly execute arbitrary code via a crafted HTML document, related to the DATA and SRC attributes of an OBJECT element. NOTE: this vulnerability exists because of an incorrect fix for CVE-2010-1214. | ||||||||||||||||||
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openoffice.org: denial of service
| Package(s): | openoffice.org | CVE #(s): | CVE-2010-2935 CVE-2010-2936 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | August 23, 2010 | Updated: | April 19, 2011 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the Red Hat advisory:
An integer truncation error, leading to a heap-based buffer overflow, was found in the way the OpenOffice.org Impress presentation application sanitized a file's dictionary property items. An attacker could use this flaw to create a specially-crafted Microsoft Office PowerPoint file that, when opened, would cause OpenOffice.org Impress to crash or, possibly, execute arbitrary code with the privileges of the user running OpenOffice.org Impress. (CVE-2010-2935) An integer overflow flaw, leading to a heap-based buffer overflow, was found in the way OpenOffice.org Impress processed polygons in input documents. An attacker could use this flaw to create a specially-crafted Microsoft Office PowerPoint file that, when opened, would cause OpenOffice.org Impress to crash or, possibly, execute arbitrary code with the privileges of the user running OpenOffice.org Impress. (CVE-2010-2936) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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php: multiple vulnerabilities
| Package(s): | php | CVE #(s): | CVE-2010-2190 CVE-2010-1914 CVE-2010-1915 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Created: | August 24, 2010 | Updated: | October 6, 2010 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Description: | From the CVE entries:
The (1) trim, (2) ltrim, (3) rtrim, and (4) substr_replace functions in PHP 5.2 through 5.2.13 and 5.3 through 5.3.2 allow context-dependent attackers to obtain sensitive information (memory contents) by causing a userspace interruption of an internal function, related to the call time pass by reference feature. (CVE-2010-2190) The Zend Engine in PHP 5.2 through 5.2.13 and 5.3 through 5.3.2 allows context-dependent attackers to obtain sensitive information by interrupting the handler for the (1) ZEND_BW_XOR opcode (shift_left_function), (2) ZEND_SL opcode (bitwise_xor_function), or (3) ZEND_SR opcode (shift_right_function), related to the convert_to_long_base function. (CVE-2010-1914) The preg_quote function in PHP 5.2 through 5.2.13 and 5.3 through 5.3.2 allows context-dependent attackers to obtain sensitive information (memory contents) by causing a userspace interruption of an internal function, related to the call time pass by reference feature, modification of ZVALs whose values are not updated in the associated local variables, and access of previously-freed memory. (CVE-2010-1915) | ||||||||||||||||||||||||||||||||||||||||||||||||||
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phpMyAdmin: cross-site scripting
| Package(s): | phpMyAdmin | CVE #(s): | CVE-2010-3056 | ||||||||||||||||||||||||||||||||
| Created: | August 23, 2010 | Updated: | September 13, 2010 | ||||||||||||||||||||||||||||||||
| Description: | From the Red Hat bugzilla:
Several cross-site scripting (XSS) vulnerabilities were found in phpMyAdmin versions prior to 2.11.10.1 and 3.3.5.1 [1]. A remote attacker was able to conduct an XSS attack using crafted URLs or POST parameters on several pages. | ||||||||||||||||||||||||||||||||||
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qspice: denial of service
| Package(s): | qspice | CVE #(s): | CVE-2010-0428 CVE-2010-0429 | ||||||||
| Created: | August 20, 2010 | Updated: | August 27, 2010 | ||||||||
| Description: | From the Red Hat advisory:
It was found that the libspice component of QEMU-KVM on the host did not validate all pointers provided from a guest system's QXL graphics card driver. A privileged guest user could use this flaw to cause the host to dereference an invalid pointer, causing the guest to crash (denial of service) or, possibly, resulting in the privileged guest user escalating their privileges on the host. (CVE-2010-0428) It was found that the libspice component of QEMU-KVM on the host could be forced to perform certain memory management operations on memory addresses controlled by a guest. A privileged guest user could use this flaw to crash the guest (denial of service) or, possibly, escalate their privileges on the host. (CVE-2010-0429) | ||||||||||
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qspice-client: man-in-the-middle vulnerability
| Package(s): | qspice-client | CVE #(s): | CVE-2010-2792 | ||||||||||||||||
| Created: | August 25, 2010 | Updated: | August 26, 2010 | ||||||||||||||||
| Description: | From the Red Hat advisory: A race condition was found in the way the SPICE Mozilla Firefox plug-in and the SPICE client communicated. A local attacker could use this flaw to trick the plug-in and the SPICE client into communicating over an attacker-controlled socket, possibly gaining access to authentication details, or resulting in a man-in-the-middle attack on the SPICE connection. | ||||||||||||||||||
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spice-xpi: symlink vulnerability
| Package(s): | spice-xpi | CVE #(s): | CVE-2010-2794 | ||||||||
| Created: | August 25, 2010 | Updated: | August 26, 2010 | ||||||||
| Description: | The SPICE firefox plugin suffers from a symbolic link vulnerability enabling a local attacker to overwrite files. | ||||||||||
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uzbl: arbitrary command execution
| Package(s): | uzbl | CVE #(s): | CVE-2010-2809 | ||||||||||||
| Created: | August 23, 2010 | Updated: | August 25, 2010 | ||||||||||||
| Description: | From the CVE entry:
The default configuration of the <Button2> binding in Uzbl before 2010.08.05 does not properly use the @SELECTED_URI feature, which allows user-assisted remote attackers to execute arbitrary commands via a crafted HREF attribute of an A element in an HTML document. | ||||||||||||||
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zabbix: cross-site scripting
| Package(s): | zabbix | CVE #(s): | CVE-2010-2790 | ||||
| Created: | August 25, 2010 | Updated: | August 25, 2010 | ||||
| Description: | Zabbix prior to 1.8.3 suffers from multiple cross-site scripting vulnerabilities; see this advisory for details. | ||||||
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zope-ldapuserfolder: authentication bypass
| Package(s): | zope-ldapuserfolder | CVE #(s): | CVE-2010-2944 | ||||
| Created: | August 25, 2010 | Updated: | August 25, 2010 | ||||
| Description: | It turns out that the zope-ldapuserfolder extension does not verify passwords when somebody logs in as the emergency user. | ||||||
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