man in the middle? - no, thank you!

No,$thank$you!MAN$IN$THE$MIDDLE$?

Daniel$Schneller$–$CenterDevice$GmbH

SSL$–$and$you’re$done™

SSL$–$and$you’re$done™

SSL$–$and$you’re$done™

…are$you?

Mac$App$Store

Mac$App$Store

Mac$App$Store

Outbank

What$happened$to$SSL?

SSL$–$Chain$of$Trust

SSL$–$Chain$of$Trust

Root$CA$Cer)ficate

SSL$–$Chain$of$Trust

Root$CA$Cer)ficate

$Intermediate$CA$Cer)ficate(s)issues

SSL$–$Chain$of$Trust

Root$CA$Cer)ficate

$Intermediate$CA$Cer)ficate(s)

Leaf$Cer)ficate

issues

issues

SSL$–$Chain$of$Trust

SSL$–$Chain$of$Trust

SSL$–$Chain$of$Trust

SSL$–$Chain$of$Trust

SSL$–$Chain$of$Trust

SSL$–$Chain$of$Trust

Just$how$many$Root$CAs$are$there?

System$Roots

System$Roots

System$Roots

Windows$8:$~350Mozilla:$~160iOS$6:$~220

Man$In$The$Middle?

Man$In$The$Middle

[Corporate]$Proxy Client

Man$In$The$Middle

[Corporate]$Proxy Client

Man$In$The$Middle

[Corporate]$Proxy Client

Man$In$The$Middle

Website [Corporate]$Proxy Client

Man$In$The$Middle

Website [Corporate]$Proxy Client

Man$In$The$Middle

Website [Corporate]$Proxy Client

Man$In$The$Middle

Website [Corporate]$Proxy Client

Man$In$The$Middle

Man$In$The$Middle

Man$In$The$Middle

Man$In$The$Middle

Man$In$The$Middle

Man$In$The$Middle

Consequences

•Monitoring

•ManipulaZon

• Sent$and$received$data$affected

• Chain\Of\Trust$formally$verified

Good$and$evil

• Debugging

• Reverse$Engineering

• Security$Audits

• Learning$and$Understanding

ReST$Debugging

Good$and$evil

• Phishing

• IdenZty$The`

• Industrial$Espionage

• …

Mac$App$Store

Mac$App$Store

Mac$App$Store

iTunes

iTunes

iTunes

Demo$1

Video$1

Video$2

Countermeasures

Reference$CerZficates

Reference$CerZficates

• Client$bundles$server$cerZficate$as$a$reference

• Compare$reference$and$cerZficate$sent$by$the$server$

• Connect$only$when$there’s$a$perfect$match

Reference$CerZficates

$Client$App$Server

Reference$CerZficates

$Client$App$Server

==

Reference$CerZficates

SecTrustResultType evaluationResult;OSStatus status = SecTrustEvaluate(srvTrust, &evaluationResult);

if (status == errSecSuccess) { if (evaluationResult == kSecTrustResultUnspecified) {

// ...

}}

• Step$1:$$Validate$Chain\of\Trust

Reference$CerZficates

SecTrustResultType evaluationResult;OSStatus status = SecTrustEvaluate(srvTrust, &evaluationResult);

if (status == errSecSuccess) { if (evaluationResult == kSecTrustResultUnspecified) {

// ...

}}

• Step$1:$$Validate$Chain\of\Trust

Reference$CerZficates

• Step$1:$$Validate$Chain\of\Trust

SecTrustResultType evaluationResult;OSStatus status = SecTrustEvaluate(srvTrust, &evaluationResult);

if (status == errSecSuccess) { if (evaluationResult == kSecTrustResultUnspecified) {

// ...

}}

Reference$CerZficates

• Step$1:$$Validate$Chain\of\Trust

SecTrustResultType evaluationResult;OSStatus status = SecTrustEvaluate(srvTrust, &evaluationResult);

if (status == errSecSuccess) { if (evaluationResult == kSecTrustResultUnspecified) {

// ...

}}

Reference$CerZficates

• Step$1:$$Validate$Chain\of\Trust

SecTrustResultType evaluationResult;OSStatus status = SecTrustEvaluate(srvTrust, &evaluationResult);

if (status == errSecSuccess) { if (evaluationResult == kSecTrustResultUnspecified) {

// ...

}}

Reference$CerZficates

• Step$1:$$Validate$Chain\of\Trust

SecTrustResultType evaluationResult;OSStatus status = SecTrustEvaluate(srvTrust, &evaluationResult);

if (status == errSecSuccess) { if (evaluationResult == kSecTrustResultUnspecified) {

// ...

}}

NSString *refPath = [[NSBundle mainBundle] pathForResource:@"reference" ofType:@"der"];

NSData *refCertData = [[NSData alloc] initWithContentsOfFile:refPath];

Reference$CerZficates

• Step$2:$Load$Reference$CerZficate

NSString *refPath = [[NSBundle mainBundle] pathForResource:@"reference" ofType:@"der"];

NSData *refCertData = [[NSData alloc] initWithContentsOfFile:refPath];

Reference$CerZficates

• Step$2:$Load$Reference$CerZficate

Reference$CerZficates

• Step$2:$Load$Reference$CerZficate

NSString *refPath = [[NSBundle mainBundle] pathForResource:@"reference" ofType:@"der"];

NSData *refCertData = [[NSData alloc] initWithContentsOfFile:refPath];

Reference$CerZficates

BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); found = [refCertData isEqualToData:certData];}

• Step$3:$Compare$cerZficates

Reference$CerZficates

BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); found = [refCertData isEqualToData:certData];}

• Step$3:$Compare$cerZficates

Reference$CerZficates

• Step$3:$Compare$cerZficates

BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); found = [refCertData isEqualToData:certData];}

Reference$CerZficates

• Step$3:$Compare$cerZficates

BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); found = [refCertData isEqualToData:certData];}

Reference$CerZficates

• Step$3:$Compare$cerZficates

BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); found = [refCertData isEqualToData:certData];}

Reference$CerZficates

• Step$3:$Compare$cerZficates

BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); found = [refCertData isEqualToData:certData];}

Reference$CerZficates

• Step$3:$Compare$cerZficates

BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); found = [refCertData isEqualToData:certData];}

Demo$2

Video

FingerprinZng

FingerprinZng

• Similar$to$Reference$CerZficate$approach

• Compares$CerZficate$Fingerprint$against$reference$value

• Server$CerZficate$not$needed$in$the$client

• Example:$$Apple$So`ware$Update

FingerprinZng$

$Client$App$Server

1122 3344 55667788 9900 AABBCCDD EEFF 9988

7766

SHA-1 Hash

FingerprinZng$

$Client$App$Server

1122 3344 55667788 9900 AABBCCDD EEFF 9988

7766

SHA-1 Hash

FingerprinZng$

$Client$App$Server

==1122 3344 55667788 9900 AABBCCDD EEFF 9988

7766

SHA-1 Hash

1122 3344 55667788 9900 AABBCCDD EEFF 9988

7766

FingerprinZng

• Schrie$1:$Chain\of\Trust$validieren

SecTrustResultType evaluationResult;OSStatus status = SecTrustEvaluate(srvTrust, &evaluationResult);

if (status == errSecSuccess) { if (evaluationResult == kSecTrustResultUnspecified) {

// ...

}}

FingerprinZng

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

• Schrie$2:$Fingerprint$berechnen

FingerprinZng

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

• Schrie$2:$Fingerprint$berechnen

FingerprinZng

• Schrie$2:$Fingerprint$berechnen

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

FingerprinZng

• Schrie$2:$Fingerprint$berechnen

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

FingerprinZng

• Schrie$2:$Fingerprint$berechnen

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

FingerprinZng

• Schrie$2:$Fingerprint$berechnen

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

FingerprinZng

• Schrie$2:$Fingerprint$berechnen

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

FingerprinZng

• Schrie$2:$Fingerprint$berechnen

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

FingerprinZng

• Schrie$2:$Fingerprint$berechnen

static NSString* const kReferenceFP = @"AC .... DC";BOOL found = NO;CFIndex crtCount = SecTrustGetCertificateCount(srvTrust);

for (CFIndex j = 0; j < crtCount && !found; j++) { SecCertificateRef cert = SecTrustGetCertificateAtIndex(srvTrust, j); NSData* certData = CFBridgingRelease(SecCertificateCopyData(cert)); NSString* fingerprint = [self sha1:certData]; found = [kReferenceFP isEqualToString:fingerprint]}

Demo$3

Video

Caveats

Caveats

• Change$of$CerZficate

• Expired

• Compromised

• Update$app$with$plenty$of$lead$Zme

• Temporarily$accept$old$and$new$cerZficates

VariaZon

VariaZon

• Check$Root\CerZficate$against$reference

• Trade\Off:$Flexibility$vs.$Security

• Updates$only$required$when$changing$Root\CA

Conclusions

Conclusions

• SSL$provides

• ConfidenZality$(encrypted)

• AuthenZcity

• CA$system$(usually)$suffiecient

•More$Security$=$More$Work

Make$informed$decisions!

Links

Sample,Code

•github.com/dschneller/mitm\no\thank\you

Tools

•github.com/ADVTOOLS/ADVcerZficator

•github.com/ADVTOOLS/ADVTrustStore

•www.apple.com/support/iphone/enterprise

•technet.microso`.com/en\us/library/cc754841.aspx

LinksTLS,Session,Cache

•developer.apple.com/library/ios/#qa/qa1727

Root6CA,Lists

•support.apple.com/kb/HT5012

•www.mozilla.org/projects/security/certs/included/

•social.technet.microso`.com/wiki/contents/arZcles/14215.windows\and\windows\phone\8\ssl\root\cerZficate\program\member\cas.aspx

•Android:$Sepngs–Security–Trusted$CredenZals

Thank$you!

QuesZons$?

daniel.schneller@centerdevice.de

$$$$$@dschneller

That’s$all.$Really.$:)

Demo$1Standard$SSL,$MITM$Root\CA$not$installiert

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