1. No,$thank$you!
MAN$IN$THE$MIDDLE$?
Daniel$Schneller$–$CenterDevice$GmbH

2. SSL$–$and$you’re$done™

3. SSL$–$and$you’re$done™

4. SSL$–$and$you’re$done™
…are$you?

5. Mac$App$Store

6. Mac$App$Store

7. Mac$App$Store

8. Outbank

9. What$happened$to$SSL?

10. SSL$–$Chain$of$Trust

11. SSL$–$Chain$of$Trust
Root$CA$Cer)ficate

12. SSL$–$Chain$of$Trust
Root$CA$Cer)ficate
$Intermediate$CA$Cer)ficate(s)issues

13. SSL$–$Chain$of$Trust
Root$CA$Cer)ficate
$Intermediate$CA$Cer)ficate(s)
Leaf$Cer)ficate
issues
issues

14. SSL$–$Chain$of$Trust

15. SSL$–$Chain$of$Trust

16. SSL$–$Chain$of$Trust

17. SSL$–$Chain$of$Trust

18. SSL$–$Chain$of$Trust

19. SSL$–$Chain$of$Trust

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

21. System$Roots

22. System$Roots

23. System$Roots
Windows$8:$~350
Mozilla:$~160
iOS$6:$~220

24. Man$In$The$Middle?

25. Man$In$The$Middle
[Corporate]$Proxy Client

26. Man$In$The$Middle
[Corporate]$Proxy Client

27. Man$In$The$Middle
[Corporate]$Proxy Client

28. Man$In$The$Middle
Website [Corporate]$Proxy Client

29. Man$In$The$Middle
Website [Corporate]$Proxy Client

30. Man$In$The$Middle
Website [Corporate]$Proxy Client

31. Man$In$The$Middle
Website [Corporate]$Proxy Client

32. Man$In$The$Middle

33. Man$In$The$Middle

34. Man$In$The$Middle

35. Man$In$The$Middle

36. Man$In$The$Middle

37. Man$In$The$Middle

38. Consequences
•Monitoring
•ManipulaZon
•Sent$and$received$data$affected
•ChainOfTrust$formally$verified

39. Good$and$evil
•Debugging
•Reverse$Engineering
•Security$Audits
•Learning$and$Understanding

40. ReST$Debugging

41. Good$and$evil
•Phishing
•IdenZty$The`
•Industrial$Espionage
•…

42. Mac$App$Store

43. Mac$App$Store

44. Mac$App$Store

45. iTunes

46. iTunes

47. iTunes

48. Demo$1
Video$1
Video$2

49. Countermeasures

50. Reference$CerZficates

51. 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

52. Reference$CerZficates
$Client$App$Server

53. Reference$CerZficates
$Client$App$Server
==

54. Reference$CerZficates
SecTrustResultType evaluationResult;
OSStatus status =
SecTrustEvaluate(srvTrust,
&evaluationResult);
if (status == errSecSuccess) {
if (evaluationResult == kSecTrustResultUnspecified) {
// ...
}
}
•Step$1:$$Validate$ChainofTrust

55. Reference$CerZficates
SecTrustResultType evaluationResult;
OSStatus status =
SecTrustEvaluate(srvTrust,
&evaluationResult);
if (status == errSecSuccess) {
if (evaluationResult == kSecTrustResultUnspecified) {
// ...
}
}
•Step$1:$$Validate$ChainofTrust

56. Reference$CerZficates
•Step$1:$$Validate$ChainofTrust
SecTrustResultType evaluationResult;
OSStatus status =
SecTrustEvaluate(srvTrust,
&evaluationResult);
if (status == errSecSuccess) {
if (evaluationResult == kSecTrustResultUnspecified) {
// ...
}
}

57. Reference$CerZficates
•Step$1:$$Validate$ChainofTrust
SecTrustResultType evaluationResult;
OSStatus status =
SecTrustEvaluate(srvTrust,
&evaluationResult);
if (status == errSecSuccess) {
if (evaluationResult == kSecTrustResultUnspecified) {
// ...
}
}

58. Reference$CerZficates
•Step$1:$$Validate$ChainofTrust
SecTrustResultType evaluationResult;
OSStatus status =
SecTrustEvaluate(srvTrust,
&evaluationResult);
if (status == errSecSuccess) {
if (evaluationResult == kSecTrustResultUnspecified) {
// ...
}
}

59. Reference$CerZficates
•Step$1:$$Validate$ChainofTrust
SecTrustResultType evaluationResult;
OSStatus status =
SecTrustEvaluate(srvTrust,
&evaluationResult);
if (status == errSecSuccess) {
if (evaluationResult == kSecTrustResultUnspecified) {
// ...
}
}

60. NSString *refPath =
[[NSBundle mainBundle] pathForResource:@"reference"
ofType:@"der"];
NSData *refCertData =
[[NSData alloc] initWithContentsOfFile:refPath];
Reference$CerZficates
•Step$2:$Load$Reference$CerZficate

61. NSString *refPath =
[[NSBundle mainBundle] pathForResource:@"reference"
ofType:@"der"];
NSData *refCertData =
[[NSData alloc] initWithContentsOfFile:refPath];
Reference$CerZficates
•Step$2:$Load$Reference$CerZficate

62. Reference$CerZficates
•Step$2:$Load$Reference$CerZficate
NSString *refPath =
[[NSBundle mainBundle] pathForResource:@"reference"
ofType:@"der"];
NSData *refCertData =
[[NSData alloc] initWithContentsOfFile:refPath];

63. 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

64. 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

65. 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];
}

66. 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];
}

67. 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];
}

68. 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];
}

69. 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];
}

70. Demo$2
Video

71. FingerprinZng

72. FingerprinZng
•Similar$to$Reference$CerZficate$approach
•Compares$CerZficate$Fingerprint$against$
reference$value
•Server$CerZficate$not$needed$in$the$client
•Example:$$Apple$So`ware$Update

73. FingerprinZng$
$Client$App$Server
1122 3344 5566
7788 9900 AABB
CCDD EEFF 9988
7766
SHA-1 Hash

74. FingerprinZng$
$Client$App$Server
1122 3344 5566
7788 9900 AABB
CCDD EEFF 9988
7766
SHA-1 Hash

75. FingerprinZng$
$Client$App$Server
==
1122 3344 5566
7788 9900 AABB
CCDD EEFF 9988
7766
SHA-1 Hash
1122 3344 5566
7788 9900 AABB
CCDD EEFF 9988
7766

76. FingerprinZng
•Schrie$1:$ChainofTrust$validieren
SecTrustResultType evaluationResult;
OSStatus status =
SecTrustEvaluate(srvTrust,
&evaluationResult);
if (status == errSecSuccess) {
if (evaluationResult == kSecTrustResultUnspecified) {
// ...
}
}

77. 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

78. 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

79. 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]
}

80. 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]
}

81. 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]
}

82. 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]
}

83. 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]
}

84. 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]
}

85. 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]
}

86. Demo$3
Video

87. Caveats

88. Caveats
•Change$of$CerZficate
•Expired
•Compromised
•Update$app$with$plenty$of$lead$Zme
•Temporarily$accept$old$and$new$
cerZficates

89. VariaZon

90. VariaZon
•Check$RootCerZficate$against$reference
•TradeOff:$Flexibility$vs.$Security
•Updates$only$required$when$changing$
RootCA

91. Conclusions

92. Conclusions
•SSL$provides
•ConfidenZality$(encrypted)
•AuthenZcity
•CA$system$(usually)$suffiecient
•More$Security$=$More$Work

93. Make$informed$
decisions!

94. Links
Sample,Code
•github.com/dschneller/mitmnothankyou
Tools
•github.com/ADVTOOLS/ADVcerZficator
•github.com/ADVTOOLS/ADVTrustStore
•www.apple.com/support/iphone/enterprise
•technet.microso`.com/enus/library/
cc754841.aspx

95. Links
TLS,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.windowsandwindowsphone8
sslrootcerZficateprogrammembercas.aspx
•Android:$Sepngs–Security–Trusted$CredenZals

96. Thank$you!

97. QuesZons$?
daniel.schneller@centerdevice.de
$$$$$@dschneller

98. That’s$all.$Really.$:)

99. Demo$1
Standard$SSL,$
MITM$RootCA$
not$installiert
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