Toorcon 11

Toorcon 11 Computer Security Conference

San Diego Gaslamp Quarter
San Diego Gaslamp Quarter, across from the Convention Center

Intro

[Toorcon] ToorCon 11 ToorCon is the 11th annual Computer Security Convention held in San Diego—this is the 6th one I've attended. It's held at the Convention Center on the bay front, with a view downtown of the Gaslamp District. It's a beautiful, walkable downtown on a sunny day and I'm inside :-O.

ToorCon has two track sessions, so I didn't catch everything, and I didn't take notes for all sessions. These notes are mine, so I may have misrepresented the speaker's remarks—but bits happen!

DVDs of this year's presentations is available from http://www.mediaarchives.com/ (not listed on website). I bought seven of their DVD's from previous, remote cons on subjects of interest—who says I don't have a life?—that'll show them.

—Dan Anderson
October 2009, San Diego, California

Tim Geo David
Toorcon organizers Tim Huynh (nfiltr8), George
Spillman (geo), and David Hulton (h1kari)
Geo and Dan Kaminsky
Dan Kaminsky (rt.). Geo (lt.)'s T-shirt says
"I slept on Kaminsky's couch and all I got
was this pillow case and towel"

Ubiquitous Computing (Keynote)

[Toorcon] Vernor Vinge Vernor Vinge, SDSU, is a retired professor and science fiction author. His notes, more accurate than these, are online (for now) at http://www-rohan.sdsu.edu/faculty/vinge/toorcon2009/

How far can ubiquitous computing get? We started with embedded systems in the 1980s, then network embedded systems. Now "nodes" know where they are, what they are, and build ad hoc networks.

Having several distributed nodes can produce spectacular output effects—can program walls, furniture, and maybe even insects and dust. Problems include power for high duty-cycle nodes, cleaning up "node guano" (dead infrastructure nodes). Wearable nodes can be a communication endpoint and be used in augmented reality (virtual environments).

Cyberspace leaks into the real world. Reality and real world becomes a "database"—with easier updates. Physical failures and attacks are more-frequently from computer, software, and communication failures. Big problem in this world is identity theft.

With ubiquitous computers, physical world becomes as volatile as the financial world. Currently, you can relay on things like gravity and air pressure. As controls become software-based, they become less stable.

Advice:

  • have heterogeneous solutions at all layers
  • find and fix software security issues and provide a secure and open infrastructure.
  • The trend to ubiquitous computation is unstoppable, leaving to complexity comparable to the biological world. As with biology, robustness is needed.

Black Operations of PKI

[Toorcon] Dan Kaminsky Dan Kaminsky, IOActive

Vulnerabilities (0-day) get the press, but according to Verizon Business, 60% of real world losses are not from software vulnerabilities, but failed authentication technology. Examples: no passwords, bad passwords, default passwords, stolen passwords, and my passwords (Dan's account was recently hacked, as was well-publicized)

What can we do?—here's schools of thought:

  • Make passwords work, barely (machine-generate, expire, prohibit simple passwords)
  • Eliminate passwords and get humans out of (password) memory business. Such as X.509 technology (smart cards).

Reality check. Business does "care enough" about authentication and has invested a lot in it. But something isn't working. Dan thinks it's X.509, the core technology of PKI, that's broken.

Another proposal is creating a second Internet from scratch and to not screw it up. This is hopeful, but naïve. It will be a never-built, never-used theoretical pile of junk.

X.509 intro. It's the identity system behind PKI. Used for SSL, IPsec (not SSH). With X.509, public keys and names are signed by trusted certificate authorities (CAs). Others validate against CA-issued certificates. X.509 in the real world as one success case—SSL (HTTPS).

How to get a X.509 Certificate?

  • Get a X.509 by first registering a name with DNS,
  • Generate a public/private keypair and send it to a CA.
  • The CA then verifies the domain name through DNS and other methods. (this is "Domain Validation")

X.509 problems:

  • Every CA can issue a certificate for every name (similar to Zimbabwe issuing US passwords).
  • Some CAs are excellent, but it's a "race to the bottom" as any other CA can issue a certificate.

DNS very good at excluding—only one DNS root. Verisign exclusively controls .com and Afilias exclusively controls .org. But with X.509, this is not possible—any X.509 CA can screw things up and they don't have accountability if they ("bad CAs') screw up (unlike DNS registers).

Interoperability is not optional—you have to authenticate not only within your organization, but to other organizations. However, X.509 can not delegate (without great pain). A new X.509 certificate always requires going back to an external CA. X.509 version 3 has something tacked on ("Name Constraints") to allow delegation, but not well supported in field. DNS, OTOH, delegates every well. X.509 allows private CAs, which cannot be done securely without Name Constraints, but some CAs hand out "god-level" intermediate CAs anyway.

Dan then talked about specific X.509 attacks, but I didn't have time to write them down. One involved lying to a CA (saying www.live.com is an "internal server" and getting a cert for it. Another involved using insecure MD5 hashing (still used by RapidSSL CA).

X.509 is very fragile, but has been around 15 years.

MD2 (less secure than MD5) is also supported still by X.509. MD2 isn't used anymore, so shouldn't be a problem in theory. Ha ha. Verisign's self-signed root certificate uses MD2 and doesn't expire until 2098. It shouldn't be self-signed, because it should be trusted because it's trusted. It's completely-meaningless crypto—you are basically saying "I am me, says I". It only gives the appearance of more security, but actually provides less (because of the insecure MD2 signature). Also, Verisign was still issuing MD2-hashed certificates up to 1998. Can attack MD2-hashed certificates by appending an old certificate and getting the same MD2 hash (similar to a MD5 attack). Can create a new intermediate CA certificate this way. Also, brute force attacks with MD2 is getting easier.

Most CAs are now reissuing certificates that don't use MD2. But unexpired certs are still around (although not issued any longer), and you can extend date of expired certs. Problem can be preemptively addressed by not supporting MD2 any longer.

Self-signed CAs and certificates. OpenSSL makes this every easy to do this. OpenSSL has protections against having multiple common names (CN), but none of this is enabled by default :-). Which CN is used if there is multiple CNs? In OpenSSL first CN wins, in CryptoAPI all works, and in Firefox/NSS last CN wins. RFC says the "most specific" CN wins!

X.509 is encoded in ASN 1, but is a travesty. ASN 1 is complex—it has 17 string times, 3 integer types. Every easy to crash under fuzzing. Used as a SQL-injection channel. ASN uses OID, 2.5.4.3 is the OID for a CN. Can attack with leading zeros, such as 2.5.4.0003. Works with IE (but not Firefox). Most CAs extract a CN and throw away all the rest (which is good). NUL character exploit in CN has been fixed in browsers.

What to do? I asked Dan what he thought the solution was, given that he didn't propose a solution. He said the solution was to use DNS with DNSSEC, then to use CAs only to provide real-world name validation. Use a hybrid solution. Don't use CAs to provide validation of the name—use DNSSEC for that. Move to DNSSEC is very good at validation and delegation. CA's are Useful as "boots on the ground" to provide semantic validation that a domain name is really tied to a specific entity (e.g., that bank-of-america.com is valid). Once a DNS name is validated (with DNSSEC), use a CA to tie the DNS name to the real world.

OK, I later asked Dan that given the horrible complexity of deploying DNSSEC, why would any sane person propose this as a solution? He said the spec is horribly complex, but like many specs, you don't have to implement all of it (such as the myriad of keys). The first step is to have the root, then the TLDs deploy DNSSEC--this greatly simplifies implementing DNSSEC for lower-level domains. Then, BIND and other DNS implementations need to provide signatures on the fly (rather than the current requirement of pre-processing the entire textual database).

Exploiting Trust-based Subdomain names

[Toorcon] Mike Bailey Mike Bailey, posts on skeptikal.org

When you set up a web application, it's common to point to a 3rd-party server with a subdomain, e.g., someremotewebapp.mydomain.com. So, if one can exploit that third-party server, one may be able to take advantage of the greater "trust" of anything under mydomain.com by other mydomain.com apps. Often, one subdomain trusts all the other subdomains (this doesn't have to be the case, but is easier to setup and configure). The third-party server is commonly a server serving banner ads. Often old DNS records are lying around that can be reused or pointed to some malicious location.

What can one do to take advantage of this weakness? Read cookies from mydomain.com, Javascript injection (with a cross-site scripting (XSS) hole), setting cookies (if not set yet for a client session). This method was used to exploit nytimes.com, gmail, expedia, facebook, for example.

Flash exploits (via cross-comain XML policy). Commonly, administrators whitelist \*.mydomain.com, allowing any SWF file to run from another subdomain.

Basic problem is humans—people trust domain names, specifically subdomains. Useful exploits include phishing, spreading malware, XSS attacks, and clicking on legitimate-looking subdomain links.

Fixes: escape input to prevent XSS, validate forms, don't use badly-coded apps (or untrusted apps), and disable Javascript and Flash (last 2 not always realistic). Prevent subdomain attacks by restricting cookies to a specific domain, audit DNS records (and purge obsolete ones), don't point DNS at third-party apps (unless they are really trusted), and don't host user content on your domain.

Organizing a Cyber-Army: Modern Botnet Architecture

[Toorcon] Brandon Enright Brandon Enright, UCSD CSE

Botnets (robot networks) or "zombie armies" exist because they make money. They make money using botnets to send spam. The spam typically has a link that a few spam receivers click on, which then directs the customer to affiliate websites (say for Viagra) and the spam sender receives the money. Older spam methods, such as open SMTP relays, are not a problem any longer.

Evolution of Botnets. A large botnet requires a Command and Control (C&C) channels on (legitimate) IRC servers to control a large botnet. It was easy to find botnet channels just by looking on IRC traffic. So, then spammers setup their own (evil) IRC servers just for C&C channels. Admins then blocked IRC, so they migrated to proprietary peer-to-peer (P2P) protocols and networks (such as W.A.S.T.E.). Botnets next evolved to use http using distributed web servers for C&C server—this is difficult to block or shutdown. The C&C server is hidden with interchangeable web proxies. This architecture looks like organized crime—the boss is hidden.

Spammers use Fast-Flux DNS to quickly switch C&C servers among several distributed servers. The A (address) record is not fixed—it points to say a thousand separate servers. Can't block because addresses are located on several networks.

Double Fast-Flux also changes the name server (NS) record, not just the A record. This requires cooperation of a (cooperating) registrar (most registrars frown on quickly-changing NS records).

Kademlia Botnet Architecture. Computers self-organize with random numbers identifying themselves. They build up a closeness-relationship among each other (by hops) stored in a distributed hash table (DHT).

Four-level Storm Botnet had workers (infected home computers sending spam) and proxies (also infected home computers). These proxies talked to a backend C&C proxy, which then talked to one of a set of distributed C&C servers. This is similar to the Russian missile train architecture—the missile trains were located at random, changing locations, so couldn't be taken out. The bottom two layers are coordinated using Overnet. A "Breath of Life" (BoL) server would promote worker computers (infected home computers) to the next level, proxy computers, when the BoL found out the worker computer had good connectivity and a static IP.

Waldedac Botnet was created after Storm (which was too easy to track). The communication between botnet layers was encrypted. Top two layers use bullet-proof hosting (from cooperating ISPs). The encryption uses AES, but is not perfect—all with the same key that changes periodically.

Conflicker Botnet Internet randomly-scanned to find hosts. Basically impossible to shut down. Protocol uses union (instead of a struct) to obscure protocol, signed/unsigned math, byte swapping, and variable length numbers. Hard to use scripting languages to emulate (must use C or assembly).

Owning Enterprise Mail via Nth-Party Software

[Toorcon] Joshua Drake & Sean Larsson Joshua J. Drake & Sean Larsson, VeriSign iDefense

Nth-party software is 3rd-party software "gone bad." That is, software adopted and modified by yet another party. It's often a problem for security because of the extra time required to get a fix out. Common examples of nth-party software is Winamp or software on Linksys routers.

Email gives a broad attack surface due to varying message formats and wide-range of file attachments. They investigated RIM's BlackBerry BES software and (platform-independent) Good Mobile Messaging Server (GMMS), which are two common remote email enterprise solutions. They found enterprise FTP sites (e.g., IBM) with useful information on GMMS software structure and its configuration.

GMMS and Outside In Found GMMS uses Oracle's (Stellnet's) "Outside In" library, which filters 400+ file formats. No way is this vulnerability-free, so Josh focused on this library. Easy to fuzz using standalone trial format conversion software from Oracle. Focused on Excel 97 format (vsxl5.dll), which has lots of problems. Found one and was able to find an exploit from sending an Excel attachment and having one user open it.

BlackBerry BES Sean focused on BlackBerry's BES (BlackBerry Enterprise Server) software. BlackBerry routers are inside the firewall. Runs as a Windows service. Sean choose reverse-engineering rather than fuzzing to find an exploit. Found BES's conversion software is Arizan's AirDoc Library (acquired by RIM). AirDoc uses zlib, ImageMagick, and PDF. Sean thought PDF was probably the easiest to exploit, so focused on that. Found one using a uninitialized table.

Vendor Recommendations RIM guys were relatively-responsive. GMMS were not responsive and ignored problems they reported. They recommend vendors that include nth-party software in their email server software follow these recommendations:

  • Think about security more. For example, are all 400 file formats important to support
  • React quickly to reported vulnerabilities
  • Be proactive—fuzz and audit code
  • Assume failures occur—use principle of least privilege with services
  • Sandbox services that must run privileged
  • Use more-granular access control. Blocking filters/extensions.

Botnets, Ransomware, Malware, and Stuff

Recent trends in malware, from a reverse-engineer point-of-view

Julia Wolf [Toorcon] Julia Wolf, Fireeye

Julia showed low-level examples from her research of various kinds of malware. I couldn't follow it all due to the detail.

Exploits First, she explained PDF and other file format exploits. PDF file format is similar to Postscript without loops or variables. PDF has objects that point to each other. To analyze, install xpdf (don't use (incomplete) pdftosrc).

One exploit was inserting DOS executable code at end of filename in PDF file, which, when saved, saved the executable code as a file. Several exploits appear to be Chinese, due to the presence of Chinese character filenames and authors in the file. XMP metadata is used for exploits.

Obsfuscation Most malware sticks a GIF or JPG in front of a file to escape virus scanners. Result is dual executable/graphic file. Example: http://www.xiaonews.cn/config.gif (don't try this at home)

Well-Done Crypto example: LuckySploit downloads as three Javascript chunks, then reassembled. First chunk is a full RSA implementation, which is used to decrypt the remaining chunks. The second chunk checks Acrobat/Flash versions and downloads appropriate exploit. Chunk three does the actual exploit.

Ransomware Used to deny someone access and request a ransom. GPCode—encrypts files with RC4 (disguised as PGP/GPG) and deletes itself. Key disguised in email.

Everyone makes same mistakes (patterns) in coding exploit code:

  • mysterious hard-coded constants
  • lots of byte ops (AL, AH, BL, etc.)
  • lots of shifts with logical operators
  • loops with nothing but math or XOR
  • followed by buffer-related file operations.

Lamest Ransomeware Ever (almost ROT-26 encoding)

  • software XORs of plaintext with a hard-coded key
  • checks for the presence of a hard-coded test file
  • encrypts files if the file isn't there
  • if you delete a hard-coded filename, it re-encrypts previously encrypted files
  • because (lame) XOR encryption used, this decrypts the file.

Other ransomware examples and comments:

  • VSCrypt—fake Trojan Encoder
  • Vundo—fake antivirus software—scareware/ransomeware
  • Virus writers often poorly-trained. For example, one code fragment converted an IP address to a string and parsed the string just to access a specific byte of the IP address. An exception is fake Anti-virus (AV) software. The Fake AV creators have money to hire real programmers.

Killerbee: Practical Zigbee Exploitation Framework

[Toorcon] Joshua Wright Joshua Wright, InGuardians

ZigBee is a low-power, low-data wireless protocol. It uses IEEE 802.15.4 and came out in 2004. Max throughput 250Kb/s, mesh or star topology, long battery life (5-year goal), 10-100 m. range, 16 non-overlapping channels. Uses AES-CCM, but network key shared for all devices.

ZigBee used because WiFi protocols are too bloated. Bluetooth uses too much power (frequency hopping), too complex. ZigBee low-cost, low-speed; used for lightweight embeddd technology. Security suffers because of low-cost and simplicity goals.

Example ZigBee uses include water spill gates, lighting, HVAC, and home/office appliances. Smart thermostats can interact with motorized blinds. Utilities relying on this for load-shedding (turning off HVAC). Lock doors with remote or over Internet or fire (insecure!). Retail use with inventory control and asset management.

KillerBee is a framework and tool for exploiting ZigBee (and 802.15.4 in general). Python software with (non-viral) BSD-license. KillerBee hardware is a AVR RZ Raven USB Stick ($40). Need custom firmware for functions beyond network sniffing (hw programmer $300).

Tools: zbid (list), zbdump, zbconvert, zbreplay, zbsniff, zbfind (passive sniffer), zbgoodfind (key recovery), zbassocflood. Wireshark has built-in support for decrypting ZigBee Network (NWK) encryption.

$ sudo zbid
Dev     Product String Serial Number 
005:002 KILLERB001     039C17FFFF25
004:002 RZUSBSTICK     61A017FFFF25

ZigBee weaknesses:

  • 802.15.4 has no replay protection; ZigBee has meager replay protection (similar to WEB/ARP problem)
  • Hardware is the new software. Can't change—compromised devices—this means whole network is compromised

ZigBee problems. How can this problem (key provisioning) be solved? No key revocation possible—key burned on hardware. ZigBee devices will become more common over time, on critical technology—the protocol is too attractive to avoid.

Killerbee available on www.willhackforsushi.com

Portplexd: mod_rewrite for TCP/IP

[Toorcon] Brandon Gilmore Brandon Gilmore

Portplexd is similar to Apache's mod_rewrite, but for TCP/IP—it remaps and multiplexes TCP/IP ports. Provides (poor) security through obsecurity and allows one to bypass firewalls. Portplexd's configure file uses regular expressions (PCRE or POSIX-style) to match IPs, ports, and even message payload.

Portplexd is lightweight, but eats up sockets if it processes http traffic. Matches per connection (with timeout), not per packet.

Available on http://code.google.com/p/portplexd

Breaking Adobe SWF (Flash) and AMF

[Toorcon] Kartik Trivedi and Clinton Kartik Trivedi and Clinton

AMF (Adobe Message Format) based loosely on SOAP. "Charles" is a tool used to interpret AMF.

SWF is Adobe's Flex file fomat (for Flash apps). Often find username/password, SQL connections, and comments in SWF files. Can decompile SWF, edit, and recompile SWF. Can decompile manually or use an automated tool, such as HP's SWFScan. SWFScan finds potential potential vulnerabilities for you. Another tool OWASP's SWFIntruder (old tool ~1997, poor functionality). More tips at https://www.flashsec.org/wiki/Software#Security_Analysis

Nmap: All Your MS Windows Boxes Are Belong To Me

Scary fast SMB/RPC scanning with Nmap

[Toorcon] Ron Bowes Ron Bowes, blog http://www.skullsecurity.org/

SMB is the MS CIFS filesystem protocol. Best book on CIFS is Bruce Peren's Implementing CIFS. Ron wrote scripts to gather information using SMB.

  • smb-os-discovery gets information on a windows box depending on what account you're using (anonymous, guest, normal user, or admin), and MS Windows version (Win 2K has the most info). Can scan MS Windows boxes around the world. Information includes MS Windows version, name, time, timezone, workgroup. Best target is a MS Windows domain server, as it's not used that often.
  • smb-enum-users finds user accounts, groups, and aliases.
  • smb-enum-shares finds sared file systems (usually don't get much info with this).
  • smb-brute gets a user list, guesses passwords, and gets privileges. Brute-forces hashes (easy). Logs into accounts when it correctly guesses passwords to get more information.
  • smb-psexec finds processes

Code Relationship Mapping

[Toorcon]

Joel Voss Joel R. Voss, AltSci Concepts

sprintf() is a good place to start in static code analysis. People always assume sprintf() overflows don't happen to them. The three big vulnerabilities are:

  • buffer overflow
  • NULL dereference
  • buffer functions (sprintf(), memcpy(), etc.)

Real code is complex and has lots of relationships. E.g., "bluez" has 104k lines of code, 349 dereferences, 186 arrays, 85 for() loops, and 641 function calls. Call graphs don't necessarily help. You need to detect if something is used after it's destroyed, which isn't obvious from a call graph.

NULL pointer checks (if (var != NULL)) doesn't solve problems. It prevents NULL derefs, but not overflows or pointer math (including struct field references).

Joel's plan is to vet the entire project, not just part of the code. Figure out every relationship in the code.

Q & A Static code analysis is done on source (not binary). Joel's not sure how his software compares with commercial software. He thinks it doesn't follow relationships fully. Joel is involved with vetting one open source project at a time.

This talk is online at htps://www.altsci.com/concepts/

Hacking the Planet with Contempt

[Toorcon] Dean Pierce Dean Pierce

Contempt is a Java/Eclipse program that provides a framework for collecting network information from multiple "Seed Servers". Contempt installs via webstart. It supports multiple users, multipe "seeds" scanning separate networks. The Seed Server is implemented a Java jar file. A Seed is a Java object that contains information and exposes methods. The Contempt GUI lists views on left, seed servers on right, More features would be nice and are planned, such as web spidering.

Source: code.google.com/p/seedsofcontempt
Google discussion group: groups.google.com/group/seedsofcontempt

Hacking Games for Autism

[Toorcon] John Eder John Eder

  • Autism has increased 1000% over last 12 years
  • Autism people have social interaction problems
  • Unknown causes (not vaccines)
  • Using traditional "penatration testing" methods to gain autism expertise (gain target info, then decide how to attack it)
  • 120 people now involved
  • Want to develop "serious games" that have a useful purpose, but are fun to use (such as Apple iPhone)
  • Example: autistic UK Hacker, 3L173 (Gary McKinnon), caught. US wants to extradite him and throw him in jail, UK wants to treat him

Disclaimer: the statements in this blog are my personal views, not that of my employer.

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