Changes in Deployment of

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Dec 4, 2013 (3 years and 6 months ago)

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Changes in Deployment of
Cryptography

Eric Murray

Usenix Security Symposium 2001

Introduction


How to measure changes in crypto
deployment?


SSL/TLS webservers


commonly used crypto software/hardware


deployed by security
-
concious admins, not
end
-
users as browsers are


easy to check


Why?

Methodology


Generate list of https URLs


Search engine queries using words from
/usr/dict/words (AltaVista ‘00, Google ‘01)


List of links to pages containing https URLs


Find https: URLs in pages


Sort for duplicates


Run
sslstats
on each https URL

Methodology


sslstats



based on OpenSSL


grabs cert and parses for


Validity


key size/algorithm


Issuer and Subject name


SSLv2: connect and get list of ciphersuites

Methodology


sslstats

continued:


SSLv3: connect using each ciphersuite in
turn


TLS: connect as SSLv3, add TLS
ciphersuites


check for same cert as SSLv2


Perl script reads
sslstats

output and
generates stats

Definitions


Servers categorized strong, meduim,
weak


“weak” server defined as:


RSA key <= 512 bits


no SSLv3/TLS ciphersuites over >= 56 bits


expired certificate


self
-
signed certificate


only SSLv2

Definitions


“medium”:


SSLv3/TLS


RSA key > 512 but <= 1000 bits


v3/TLS ciphersuites >= 56 bits but < 64 bits


“strong”:


SSLv3/TLS


RSA key > 1000 bits


v3/TLS ciphersuites >= 64 bits

Results


2000 survey:


57% strong


10% medium


31% weak


2001 survey:


71% strong


5% medium


23% weak

Results: Weak Server Types


Weak servers by type: 2000 2001

Microsoft
-
IIS 37% 35%

Apache 17% 23%

no name 15% 5%

Netscape
-
Enterprise 13% 21%

Stronghold 7% 4%

WebSitePro 3% 1%

“unknown” 2% 4%

Results: Weak Server Details


Percent of weak servers surveyed:


2000: 2001:

Server key <= 512 bits: 81% 72%

weak v3/TLS ciphersuites: 28% 26%

expired cert: 10% 16%

self
-
signed cert: 3% 8%

only does SSLv2: 1% 6%

Results: Server Details


Percent of all servers surveyed:







2000: 2001:

Server key <= 512 bits: 25% 17%

weak SSLv3/TLS suites: 9% 6%

expired cert: 3.1% 3.7%

self
-
signed cert: .8% 2.0%

only does SSLv2: .4% 1.4%

RSA Server Key size


Key bits 2000 2001

2048 .2% .2%

1024 70% 80%

>= 1000 2% .7%

>= 768 2% 1%

>512
-

0%

<= 512 25% 17%

Protocol Support


2000 2001

Servers supporting:

SSLv2 96% 93%

SSLv3 99% 98%

TLSv1 71% 76%

SSLv2 Ciphersuite Support

Ciphersuite: 2000 2001

RC4 Export 40 MD5 99% 98%

RC2 Export 40 MD5 97% 96%

RC4 128 MD5 86% 90%

DES EDE3 MD5 85% 89%

DES 64 MD5 85% 88%

RC2 128 MD5 84% 88%

SSLv3 Export Ciphersuites

Ciphersuite: 2000 2001

RSA RC4 40 MD5 99% 79%

RSA RC2 40 MD5 73% 87%

RSA DES 40 SHA 56% 44%

DHE RSA DES 40 SHA 24% 30%



SSLv3 non
-
Export ciphersuites

Ciphersuite: 2000 2001

RSA DES SHA 75% 76%

RSA 3DES SHA 74% 61%

RSA RC4 SHA 63% 64%

DHE RSA DES SHA 24% 29%

DHE RSA 3DES SHA 24% 30%

RSA IDEA SHA 21% 26%

TLSv1 Export Ciphersuites

Ciphersuite: 2000 2001

RSA RC4 40 MD5 100% 100%

RSA Exp1024 RC4 MD5 100% 100%

RSA Exp1024 DES SHA 91% 85%

RSA Exp1024 RC2 MD5 90% 84%

RSA Exp1024 RC4 SHA 83% 83%

RSA RC2 40 MD5 75% 76%

TLSv1 non
-
export suites

Ciphersuites: 2000 2001

RSA DES SHA 77% 78%

RSA 3DES SHA 76% 78%

RSA RC4 SHA 72% 75%

DHE RSA DES SHA 25% 36%

DHE DSS 3DES SHA 25% 36%

RSA IDEA SHA 25% 32%