Title: VERNIER Virtualized Execution Realizing Network Infrastructures Enhancing Reliability
1VERNIERVirtualized Execution Realizing Network
Infrastructures Enhancing Reliability
- VERNIER Project Team
- DARPA Application Communities Kickoff Meeting
- July 7, 2006
2Outline
- Background
- Project Overview
- Objectives
- Project Scope
- Research Challenges
- Breakthrough Capabilities
- Expected Results
- Team Key Personnel and Roles
- Technical Approach
- Scenario Exemplars
- Project Plan Schedule and Milestones
- Experimentation and Evaluation
- Technology Transition Plan
3Background
- Commercial-off-the-shelf (COTS) software
- Large organizations, including DoD, have become
dependent on it - Yet, most COTS software is not dependable enough
for critical applications - Security breaches
- Misconfiguration
- Bugs
- Large, homogeneous COTS deployments, such as
those in DoD, accentuate the risk, since many
users - Experience the same failures caused by the same
vulnerabilities, configuration errors, and bugs - Suffer the same costly, adverse consequences
- Alternatives, such as government-funded
development of high-assurance systems present
significant barriers in - Cost
- Functionality
- Performance
4VERNIER Project Objectives
- Develop new technologies to deliver the benefits
of scaling techniques to large application
communities - Provide enhanced survivability to the DoD
computing infrastructure - Enhance the cost, functionality, and performance
advantages of COTS computing environments - Investigate and develop new technologies aimed at
enabling communities of systems running similar,
widely available COTS software to perform more
robustly in the face of attacks and software
faults - Deliver a demonstrated, functioning,
transition-ready system that implements these new
AC survivability technologies - Technical approach Augmented virtual machine
monitor - Commercial transition partner VMware, Inc.
5Project Scope
- Collaborative detection and diagnosis of failures
- Collaborative response to failures
- Advanced situational awareness capabilities
- Collective understanding of community state
- Predictive capability Early warning of potential
future problems - Key goal turn the size and homogeneity of the
user community into an advantage by converting
scattered deployments of vulnerable COTS systems
into cohesive, survivable application communities
that detect, diagnose, and recover from their own
failures - What COTS?
- Microsoft Windows, IE, Office suite, and the like
6Research Challenges
- Extracting behavioral models from binary programs
- Breakthrough novel techniques required
- Quasi-static state analysis for black-box
binaries -
- Scaled information sharing
- Networked application communities sharing
knowledge about the software they run - Intelligent, comprehensive recovery
- Predictive situational awareness
- Automatic, easy-to-understand gauges
7Breakthrough Capabilities
8Expected Results and Impact
- COTS Product (VMware) with breakthrough
capabilities for application communities - Scalability to 100K nodes running augmented
VMware and custom Vernier software - Automatic collaborative failure diagnosis and
recovery - Survivable robust system
- Community-aware solution
9VERNIER Team
- SRI International, Menlo Park, CA
- Patrick Lincoln, Principal Investigator
- Steve Dawson, Project manager integration
- Linda Briesemeister, Knowledge sharing
collaborative response - Hassen Saidi, Learning-based diagnosis code
analysis situation awareness - Stanford University
- John Mitchell, Stanford PI code analysis
host-based detection and response - Dan Boneh, Knowledge sharing protocols
- Mendel Rosenblum, VMM infrastructure
collaborative response transition liaison - Palo Alto Research Center (PARC)
- Jim Thornton, PARC PI configuration monitoring
and response situation awareness - Dirk Balfanz, Community response management
- Glenn Durfee, Configuration monitoring and
response situation awareness - Technology transition partner VMWare, Inc.
10John Boyds OODA Loop
Observe
Orient
Decide
Act
ImplicitGuidance Control
ImplicitGuidance Control
UnfoldingCircumstances
CulturalTraditions
Observations
Decision(Hypothesis)
GeneticHeritage
Analyses Synthesis
Action(Test)
FeedForward
FeedForward
FeedForward
NewInformation
PreviousExperience
OutsideInformation
UnfoldingInteractionWithEnvironment
UnfoldingInteractionWithEnvironment
Feedback
Feedback
Note how orientation shapes observation, shapes
decision, shapes action, and in turn is shaped by
the feedback and other phenomena coming into our
sensing or observing window. Also note how the
entire loop (not just orientation) is an
ongoing many-sided implicit cross-referencing
process of projection, empathy, correlation, and
rejection. From The Essence of Winning and
Losing, John R. Boyd, January 1996.
Defense and the National Interest,
http//www.d-n-i.net, 2001
11VERNIER Technical Approach
12Notional Host System Architecture
13An Abstraction-Based Diagnosis Capability for
VERNIER
14Objectives
- Based on the general principle much of security
amounts to making sure - that an application does what it is suppose to
do.. and nothing else! - Build models of applications behaviors (what the
application is suppose to do). - Monitor applications behavior and report
malfunctions and unintended behaviors (deviations
from behavior). - Use the recorded execution traces as raw data to
a set of abstraction-based diagnosis engines (why
did the deviation from good intended behavior
occurredto the extent to which we can do a good
job answering such question). - Share the state of alerts and diagnosis among the
nodes of the community (sharing the bad news.but
also the good ones!). - Aggregate the diagnosis outputs and the alerts
into a situation awareness gauge.
15Global situation awareness
Situation Awareness Gauge UI
Secure Knowledge Sharing Network
Collaborative diagnosis, collaborative response
Collaborative Response
Learning-Based Diagnosis
Local diagnosis, local response
Quasi-Static Code Analysis
Configuration Analysis
Network Traffic Analysis
INCREASED APPLICATION COMMUNITY SURVIVABILITY
Safe execution
Runtime data
Monitoring and Control App OS
Execution,Configuration, Network Traffic
Dynamic VMM
VERNIER OS Base
VM Kernel
16Approach
- We combine a set of well known and well
established techniques - building increasingly accurate models of
applications behaviors - Static analysis combined with predicate
abstraction to build Dyke and CFG models used for
static analysis-based intrusion detection - Implement mechanisms for monitoring sequences of
states and actions of an application for the
following purposes - Check if a known bad sequence is executed
(signature-based!) - Check for previously unknown variations of known
bad sequences (correlation!) - Find root-causes for unexpected malfunction and
malicious exploits (Diagnosis) - Diagnosis is performed using techniques borrowed
from - Delta-debugging (root-cause diagnosis)
- Anomaly detection (correlation)
- The situation awareness gauge is implemented as a
platform independent web interface
17Monitoring-Based Diagnosis
- We combine these techniques into two phases
- Monitoring Applications are monitored and
sequences of executions along with configurations
are stored. - Diagnosis Differences between good runs and bad
runs are the first clues used for diagnosis - Traces of executions are sequences of
- System calls
- Method calls
- Changes in configurations
- The more information is stored, the better chance
that malfunctions and malicious behaviors are
properly diagnosed.
18Quasi-static binary analysis and predicate
abstraction-based intrusion detection
- Use static analysis for recovering the control
flow graph the application. - CFG generated by compliers for source code.
- Recover class hierarchy for object code of OO
applications. - Build a pushdown system which is a model that
represents an over approximation of the sequences
of methods and system calls of the application. - Deal with context sensitivity to match exit calls
to return locations. - Use predicate abstraction and data flow analysis
to refine the pushdown system and obtain a more
accurate model. - Improving the knowledge about arguments to
monitored calls.
19Better Models and Better Monitoring
- We are not just interested in detection
intrusions, but by - also generating high-level explanations of why an
- application deviates from its intended behavior.
- CFG and Dyke models are all over-approximations
of the applications behavior (potential attacks
are only discovered when the application behavior
deviates from the model). - We will use the runs of the application to
generate under-approximations of the applications
behavior! - Alternatively, ever model representing an
over-approximation has a dual that represents an
under-approximation (over and under-approximations
dont have to be the same type of models!). - We will combine over and under approximation to
reduce the risk of missing possible attacks. - We will refine the over and under approximations
to improve the application model.
20Combining over and under approximations
Over approximation (constructed by static
analysis)
Under approximation (constructed from runs)
21What if we dont have a model of the application?
- We can monitor the application as a blackbox and
intercept system calls - Learn a model of good behaviors
- Learn a model of bad behaviors
- Anomalies are difference between good and bad
behaviors - Borrow from delta-debugging techniques to find
root-causes of misbehaviors
22Analyzing Differences between runs
- There are many differences between execution
traces - Could consider arbitrary lengths of different
sub-sequences - Difference of length k should be considered where
k is defined depending on the application, the
size of the collected data, and the sensitivity
of the analysis
23Delta Differences k2
good run
bad run
a b b b b c c b b d
a b b b b c c b b d
Both sequences have the same set of 2-events
sequences. This means that, k needs to be
increased and that k2 is A too abstract way of
distinguishing the two sequences
24Delta Differences k3
25Diagnosis
- One of the 6 sequences that are not common to the
two runs is the source of the problem which
one?!. We can rank the sequences in order of
importance based on - Application specific criteria use distance to
common sequences for every application-specific
origin of a sequence (e.g, process identity, or
user identity) - Application-independent criteria use distance to
common sequences - Use distance to common sequences or known bad
sequences by ignoring order of execution of calls - Increasing k provides a better explanation, but
generates a large number of sequences.
26More abstraction
- There are more good runs than bad ones!. We need
to compare the bad runs to the union of good
runs union of good runs with a single sequence
cancel out the one bad run that contains all
those sequences! - Use average-sequence-weight ranking
27Situation Awareness Gauge
28Situation Awareness Gauge
- Implemented as a platform independent web
interface (e.g. ruby on rails) - Content is defined by the databases content
attacks, failures, diagnosis, etc - Gauges a simple Displays of number of attacks and
failures and various parameters - Provide a user with the possibilities of
initiating responses and diagnosis activities in
other nodes via the database
29Configuration-based Detection, Diagnosis,
Recovery, and Situational Awareness
30Importance of Configuration
- Static configuration state highly correlated with
system behavior - Many attacks/bugs/errors introduced by way of a
substantive change to configuration - A central problem in system administration is
the construction of a secure and scalable scheme
for maintaining configuration integrity of a
computer system over the short term, while
allowing configuration to evolve gradually over
the long term Mark Burgess, author of cfengine
31AC Opportunity
- Leverage scale of population to learn what are
bad states in configuration space
Today Every configurationchange is an
uncontrolledexperiment
AC Future Configurationchanges managed as
controlledreversible trials
32Live Monitoring of Configuration State
- State analysis
- Comparative diagnosis
- Vulnerability assessment
- Clustering similar nodes and contextualizing
observations - Detect change events
- Cluster low-level changes into transactions
- Log events for problem detection, mitigation and
user interaction - Share events in real-time for situational
awareness - Active learning
- Automated experiments to isolate root causes
- Managed testing of official changes like patch
installation
33Live Control of Configuration State
- Modification for Reversibility and
Experimentation - Coarse-grained VM rollback
- Medium-grained Installer/Uninstaller activation
- Fine-grained Direct manipulation of low-level
state elements - Prevention
- In-progress detection of changes
- Interruption of change sequence
- Reversal of partial effects
34Identifying Badness
- Objective Deterministic Criteria
- Rootkit detection from structural features
- Published attack signatures
- Objective Heuristic Criteria
- Performance outside of normal parameters
- Subjective End-User Report
- Dialog with user to gather info, e.g. temporal
data for failure appearance - Administrative Policy
- Rules specified by administrators within community
35Local Components
Community
3
App VM
VERNIER VM
Experimental VM
COTS
Console(UI)
Comm
Diag
App 1
App 2
App 1
App 2
Agent
Agent
VERNIER Monitor/Control
1
1
App OS
App OS
VERNIER OS Base
2
VMM (VM Kernel)
36Key Interfaces
VERNIER-Agent (TCP/IP, XML?) Registry change
events Filesystem change events Install
events Manipulate registry Manipulate
filesystem Control System Restore
VERNIER-VMM (?) Suspend Resume Checkpoint Revert C
lone Reset Lock memory Process events Read
memory Read/write disk
1
2
3
- VERNIER-Community
- (?)
- Cluster management
- Experience reports
- Unknown
- Prevalent
- Known Bad
- Presumed Good
- State exchange
- Experiment request/response
37Local Functions
NetworkTap
Communication Manager
Console
ResponseController
Analysis Diagnosis
Configuration Analysis
AgentInside
Event Stream
BehaviorAnalysis
TrafficAnalysis
Local DB Local condition detail Event
logs Labeled condition signatures State
snapshots Experimental data
VMM
Firewall
38Adapting and Extending Host-based, Run-time Win32
Bot Detection for VERNIER
39Overview
- Background on Stanfords botnet research
- Plans for adapting and extending this work for
application to VERNIER
40Exploit botnet characteristic ongoing command
and control
- Network-based approaches
- Filtering (protocol, port, host, content-based)
- Look for traffic patterns (e.g. DynDNS Dagon)
- Hard (encrypt traffic, permute to look like
normal traffic, ) botwriters control the
arena. - Host-based approaches
- Ours Have more info at host level.
- Since the bot is controlled externally, use this
meta-level behavioral signature as basis of
detection
41Our approach
- Look at the syscalls made by a program
- In particular at certain of their args our
sinks - Possible sources for these sinks
- local mouse, keyboard, file I/O,
- remote network I/O
- An instance of external control occurs when data
from a remote source reaches a sink - Surprisingly works really well for all bots
tested (ago, dsnx, evil, g-sys, sd, spy), every
command that exhibited external control was
detected
42Big picture
43Design
44Two modes
- Cause-and-effect semantics
- Tight relationship between receipt of some data
over network and subsequent use of some portion
of that data in a sink - Correlative semantics looser relationship
- Use of some data that is the same as some data
received over the network - Why necessary?
45Behaviors ideally disjoint_at_ lowest level in
call stack
46Results
- Looked at 6 bots agobot, dsnxbot, evilbot,
g-sysbot, sdbot, spybot - At least 4 have totally indep code bases
- g-sys non-trivially extends sd
- Spybot borrows only syn flood implem from sd
- Wide variation in implementation
- Every cmd that exhibited external control
detected almost every instance external control
flagged (3 false negatives)
47Results
48Correlative semantics
- Why necessary
- Why bots with C library functions statically
linked in unconstrained OOB copies - In general almost as good as cause-and-effect
semantics (stat vs. dyn link) - Exceptions cmds that format recvd params (e.g.
via sprintf)
49Comparison
50Comparison
51Benign program testing
- Tested against some benign programs that interact
with the network - Firefox, mIRC, Unreal IRCd
- 3 contextual false positives
- IRCd sent on X heard on Y
- Firefox dereferencing embedded links
- Artificial false positives quite a few
- mIRC DCC capabilities
- Firefox saving contents to a file,
52False positives
- contextual false positives not present in bots
- external control heuristic correctly detected but
these actions under these circumstances widely
accepted as non-malicious - artificial false positives not present in bots
- def of external control implies no user input
agreeing to particular behavior - but we dont track explicitly clean data (that
received via kb, mouse) - spurious false positives
- any other incorrect flagging of external control
53Our mechanism review
- Single behavioral meta-signature detects wide
variety of behaviors on majority of Win32 bots - Resilient to differences in implementation
- Resilient in face of unconstrained OOB copies
- Resilient to encryption w/some constraints
- Resilient to changes in command-and-control
protocol (e.g. from IRC to HTTP) and parameters
(e.g. for rendezvous point)
54Plans for VERNIER
- (1) Reimplement BotSwat
- Using correlative semantics
- With improved statistical analysis comparing
contents of buffers received over the network to
arguments of selected syscalls - Probably as an entirely kernel-space
implementation - May leverage some Livewire support to confirm
integrity of BotSwat and its components - May also leverage Livewire support to enable
better resilience to bot use of private
encryption functions - Using its watch memory range X (and let me know
when it changes) functionality
55Plans for VERNIER
- (2) Confirm BotSwat works at detecting back-door
programs - Obtain various samples of these programs
- Determine whether additional syscalls might need
to be hooked in order to provide better coverage
of the functionality exported by these programs
56Plans for VERNIER
- (3) Feasibility of simple approach to detecting
keyloggers - If it is the case that the API call to insert
self into the call chain for receiving keyboard
input (for an arbitrary window, not owned by the
calling process) eventually traps to a system
call, then this is a simple extension to BotSwat
(a new syscall to hook) - Otherwise, we need to provide a user-space
component to achieve this - Any process that signs itself up to receive
keyboard input not destined for that process is
suspect - Can extend this paradigm to trap calls to read
another processs memory - Win32 API has ReadProcessMemory function call
that enables one process to read another
processs memory contents (under certain
circumstances)
57Plans for VERNIER
- (4) Leverage Virtual Machine Introspection (VMI)
IDS technology to - Confirm integrity of kernel component of BotSwat
- Confirm integrity of keyboard/mouse drivers (to
ensure that no process is able to obtain
keyboard/mouse input via replacing the relevant
kernel-mode device drivers) - Possibly also augment BotSwats resilience to
target programs use of private encryption
functions, and the like
58Plans for VERNIER
- (5) Botnet mitigation whistleblower
- Once some bot B is detected on some host machine
via BotSwat, obtain from B (programmatically) the
CC parameters in order to prevent CC traffic
for that botnet from entering or leaving the DoD
network - Basically, push out firewall filter
- Also push sample of bot executable to
anti-malware scanner so that it can generate a
signature for this malware executable
59Plans for VERNIER
- (6) Botnet RD
- After detecting a bot and pushing out filters, we
would like to be able to poke that bot
(programmatically) in a controlled environment - Get it to generate variants of some exploit where
those variants could be used as input to an
automated vulnerability signature generator - Bot would then be operating effectively as a flow
classifier - Especially for zero-day exploits (or others that
do not already have a NIDS signature) - Requires learning the command used by the bot to
generate such scan/spread packets as well as
learning how to gain control of the bot - Note this is not attempting to solve the problem
of automated vulnerability signature generation,
but simply to get the bot to act as a flow
classifier
60Plans for VERNIER
- (7) Setting the stage generating a version of
the bot that will not trip anti-malware signature
scanners - From Christodorescu/Jha (Testing Malware
Detectors), we have techniques for performing
source-code-level obfuscations, including
variable renaming and encapsulating/encrypting
portions of the source code - Christodorescu/Jha showed that the major
anti-virus scanners performed very poorly in
response to encapsulation using hex encoding
61Knowledge Sharing in VERNIER
62Knowledge Sharing
- Need Communication is the core concept of a
community - Application communities rely on ability to share
knowledge Reliable, Efficient, Authentic, Secure - Approach two-tier peer-to-peer platform
- Tuple space (ala Linda)
- Considering JXTA, jxtaSpaces implementation of
tuple spaces - Two-tier for better scalability
- If needed, hypercube hashtable index (ala
Obreiter and Graf) - Benefits Reliable, efficient (local) knowledge
sharing - Competition Other possible methods for knowledge
sharing include explicit messaging, centralized
database, and statically indexed knowledge
structures. - Other approaches lack scalability, are
unreliable, and can bedifficult to secure
63Knowledge Sharing Levels
- Lower level (within a cluster)
- Tuple space (ala Linda (Gelernter))
- Simple queries
- (, name, ) returns records regarding name
- Concurrent access and update
- Higher level (supernodes)
- Nodes aggregate knowledge of an entire cluster
- Use abstraction to summarize current situation
- Application-level multicast to push out summaries
- Supernode pushes all summary updates into local
tuple space
64Group Communication
- Group communication is key
- For higher level, certain usual assumptions
- Reliable delivery
- Ordered message delivery
- Spread (www.spread.org) as a basis for
implementation of group communication - Building on secure spread and progress software
(progress.com)s more secure, reliable, scalable
variants of spread
65Group Communication Security and Privacy
Secrecy and Authenticity
- Security and privacy are critical aspects of
VERNIER - Must authenticate reports and ensure correctness
- Confidentiality of reports
- Protecting user privacy (my files, my keystrokes)
- Protect aspects of applications
- Protect configuration information
- Protect vulnerability detection information
- Community members send status reports to local
supernode - Reports propagated throughout network
66Group Communication Security
- Defense against
- network attacks sending forged messages to
supernodes - PKI
- Compromised community member sending false
reports - statistical anomaly detection (eg EMERALD)
- Virtualization
- Any report generated within compromised virtual
machine must be consistent with what is observed
outside the virtualization layer
67Group Communication Security
- Secure audit logs
- Secure log of all P2P status reports
- Enable post-mortem analysis on detected attacks
- Cryptographic protection of log (Boneh, Waters)
- Sanitizing stats reports
- Status reports reveal private information
- Special encryption enabling read only by
credentialed membersand search (as in search
over encrpyted database) by community - Mitigating denial of service attacks on
supernodes - Re-election of supernodes when under attack
- Securing configuration update messages
- PKI authenticating legitimate reports from
community members
68VERNIER Scenarios, Schedule, and Plans
69Example Scenarios / Use Cases
- Browser crash demonstrate both local crash
recovery from a nonmalicious failure and
proactive community avoidance of the same failure - Simple case repeatable Web browser crash occurs
when visiting a particular URL - Local diagnosis launch one or more copies of the
VM, rolled back to a known good state play back
step-by-step, observe that visiting the URL
always causes the crash - Local response quarantine the URL
- Collaborative diagnosis problem reported to the
community other installations attempt to
replicate the problem, correlate observed
behavior with relevant configuration details,
discover that the problem occurs only for browser
version X or earlier - Collaborative response recommend community-wide
upgrade - More complex variations could involve situations
in which the circumstances leading to the browser
crash involve multiple steps or interactions with
other software
70Example Scenarios / Use Cases (2)
- Phishing scenario show how VERNIER can mitigate
threats even when the attack is unknown and
requires (unwitting) human participation - Cleverly constructed e-mail induces some key
individuals to run a malicious program that
subsequently interferes with their ability to
send and/or receive e-mail - Local diagnosis detect and correlate the
installation actions of the unknown program
separately, affected users report difficulty with
e-mail VERNIER runs an experiment with a
checkpointed VM to determine possible association
with newly installed program - Local response malicious program automatically
removed (possibly by reverting to checkpointed
VM) - Collaborative diagnosis VERNIER instances share
information about the installed program even
before users report a problem community observes
use of unknown software, raising level of
suspicion - Collaborative response warning to community
against activity leading to installation of
malicious program
71Example Scenarios / Use Cases (3)
- Patching scenario demonstrate mitigation of
nonmalicious threats such as new software bugs - Variation on the phishing scenario, where
installation of a seemingly beneficial software
patch has unintended side effects or introduces a
new bug not observed previously
72Schedule and Milestones
73Experimentation and Evaluation
- Project testbed
- Cluster of 300 virtual hosts
- 30 server-class physical hosts
- 10 virtual nodes per server
- Housing and cluster configuration yet to be
determined - Single cluster in one location?
- Three clusters, one at each participant site?
Current plan - Software
- Host OS Linux
- Guest (community) OS Microsoft Windows
- Applications IE browser (possibly others) MS
Office - Simulations and scalability
- Financially infeasible to scale to thousands of
nodes - Plan is to use hybrid simulation to test
scalability - Real (live) nodes provide actual data
- Simulated nodes use synthesized data generated by
perturbing data collected from real clusters
supernodes
74Success Criteria
- Metrics and targets (team-defined)
- False positives (FP) / False negatives (FN)
- Phase 1 FP lt 10, FN lt 20
- Phase 2 FP lt 1, FN lt 2 (order of magnitude
improvement) - Percent loss of network availability
- Phase 1 At most 20 per node, with at most 80
over any 500ms interval - Phase 2 At most 5 per node, with at most 20
over any 500ms interval - Average time to recovery
- Phase 1 Assuming a fix exists (not a FN), at
most 30 minutes to recover the entire community - Phase 2 At most 10 minutes
- Average network and computational overhead
- No more than 30 slowdown for applications
- No more than 100 KB/s average VERNIER-induced
network traffic per node - Percent accuracy of prediction
- Phase 1 Effects of problems predicted within 15
minutes of onset set of nodes wrongly predicted
(either way) differs by no more than 40 of
actual - Phase 2 Prediction within 5 minutes predicted
set differs by no more than 20
75Technology Transition
- Ultimate goal of VERNIER is a COTS solution
- Transition partner VMware, Inc.
- Supporting VERNIER initially by providing VMware
licenses for the testbed - May provide limited technical assistance in
developing necessary VERNIER-to-VMM APIs (details
currently under discussion) - Have agreed to define their own success criteria
for the technology - Functionality, performance, cost, and other
relevant goals that, if met, would lead VMware to
pursue further development and integration of
VERNIER technology into the VMware product line - Initial response suggests general agreement with
the metrics weve already proposed (may want to
tweak the numbers a bit), plus - Breadth of operating system support
- Breadth of application support
76Next Steps
- VERNIER team workshop
- Full day (at least)
- Brainstorming and detailed planning
- Target date week of July 17
- Continue discussions with VMware on success
criteria, etc.