FreeBSD Security Advisory FreeBSD-SA-06:19.openssl
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 = FreeBSD-SA-06:19.opensslSecurity Advisory The FreeBSD Project Topic: Incorrect PKCS#1 v1.5 padding validation in crypto(3) Category: contrib Module: openssl Announced: 2006-09-06 Affects:All FreeBSD releases. Corrected: 2006-09-06 21:18:26 UTC (RELENG_6, 6.1-STABLE) 2006-09-06 21:19:21 UTC (RELENG_6_1, 6.1-RELEASE-p6) 2006-09-06 21:20:08 UTC (RELENG_6_0, 6.0-RELEASE-p11) 2006-09-06 21:20:54 UTC (RELENG_5, 5.5-STABLE) 2006-09-06 21:21:50 UTC (RELENG_5_5, 5.5-RELEASE-p4) 2006-09-06 21:22:39 UTC (RELENG_5_4, 5.4-RELEASE-p18) 2006-09-06 21:23:16 UTC (RELENG_5_3, 5.3-RELEASE-p33) 2006-09-06 21:24:04 UTC (RELENG_4, 4.11-STABLE) 2006-09-06 21:24:54 UTC (RELENG_4_11, 4.11-RELEASE-p21) CVE Name: CVE-2006-4339 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit URL:http://security.freebsd.org/. I. Background FreeBSD includes software from the OpenSSL Project. The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, full-featured, and Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library. PKCS#1 v1.5 is a standard for padding data before performing a cryptographic operation using the RSA algorithm. PKCS#1 v1.5 signatures are for example used in X.509 certificates. RSA public keys may use a variety of public exponents, of which 3, 17, and 65537 are most common. As a result of a number of known attacks, most keys generated recently use a public exponent of at least 65537. II. Problem Description When verifying a PKCS#1 v1.5 signature, OpenSSL ignores any bytes which follow the cryptographic hash being signed. In a valid signature there will be no such bytes. III. Impact OpenSSL will incorrectly report some invalid signatures as valid. When an RSA public exponent of 3 is used, or more generally when a small public exponent is used with a relatively large modulus (e.g., a public exponent of 17 with a 4096-bit modulus), an attacker can construct a signature which OpenSSL will accept as a valid PKCS#1 v1.5 signature. IV. Workaround No workaround is available. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE, or to the RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, RELENG_5_3, or RELENG_4_11 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 4.11, 5.3, 5.4, 5.5, 6.0, and 6.1 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch http://security.FreeBSD.org/patches/SA-06:19/openssl.patch # fetch http://security.FreeBSD.org/patches/SA-06:19/openssl.patch.asc b) Execute the following commands as root: # cd /usr/src # patch /path/to/patch c) Recompile the operating system as described in URL: http://www.freebsd.org/handbook/makeworld.html and reboot the system. NOTE: Any third-party applications, including those installed from the FreeBSD ports collection, which are statically linked to libcrypto(3) should be recompiled in order to use the corrected code. VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - - RELENG_4 src/crypto/openssl/crypto/rsa/rsa_sign.c1.1.1.1.2.6 RELENG_4_11 src/UPDATING 1.73.2.91.2.22 src/sys/conf/newvers.sh 1.44.2.39.2.25 src/crypto/openssl/crypto/rsa/rsa_sign.c1.1.1.1.2.5.6.1 RELENG_5 src/crypto/openssl/crypto/rsa/rsa_sign.c1.1.1.6.4.1 RELENG_5_5 src/UPDATING 1.342.2.35.2.4 src/sys/conf/newvers.sh 1.62.2.21.2.6 src/crypto/openssl/crypto/rsa/rsa_sign.c 1.1.1.6.16.1 RELENG_5_4 src/UPDATING1.342.2.24.2.27 src/sys/conf/newvers.sh 1.62.2.18.2.23 src/crypto/openssl/crypto/rsa/rsa_sign.c1.1.1.6.8.1 RELENG_5_3 src/UPDATING1.342.2.13.2.36 src/sys/conf/newvers.sh
Re: [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:19.openssl
skk です． うーん，どんな問題が起きるのか，いまいちピンと来ないので，重要度がわか らないですが，こんなのが出てます． 調べてませんが，多分，他の OS でも同様の問題があるのではないでしょうか． time: Wed, 6 Sep 2006 21:59:34 GMT subject: [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:19.openssl message-id: [EMAIL PROTECTED] FreeBSD Security Advisories [EMAIL PROTECTED] wrote as follows -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 = FreeBSD-SA-06:19.opensslSecurity Advisory The FreeBSD Project Topic: Incorrect PKCS#1 v1.5 padding validation in crypto(3) Category: contrib Module: openssl Announced: 2006-09-06 Affects:All FreeBSD releases. Corrected: 2006-09-06 21:18:26 UTC (RELENG_6, 6.1-STABLE) 2006-09-06 21:19:21 UTC (RELENG_6_1, 6.1-RELEASE-p6) 2006-09-06 21:20:08 UTC (RELENG_6_0, 6.0-RELEASE-p11) 2006-09-06 21:20:54 UTC (RELENG_5, 5.5-STABLE) 2006-09-06 21:21:50 UTC (RELENG_5_5, 5.5-RELEASE-p4) 2006-09-06 21:22:39 UTC (RELENG_5_4, 5.4-RELEASE-p18) 2006-09-06 21:23:16 UTC (RELENG_5_3, 5.3-RELEASE-p33) 2006-09-06 21:24:04 UTC (RELENG_4, 4.11-STABLE) 2006-09-06 21:24:54 UTC (RELENG_4_11, 4.11-RELEASE-p21) CVE Name: CVE-2006-4339 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit URL:http://security.freebsd.org/. I. Background FreeBSD includes software from the OpenSSL Project. The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, full-featured, and Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library. PKCS#1 v1.5 is a standard for padding data before performing a cryptographic operation using the RSA algorithm. PKCS#1 v1.5 signatures are for example used in X.509 certificates. RSA public keys may use a variety of public exponents, of which 3, 17, and 65537 are most common. As a result of a number of known attacks, most keys generated recently use a public exponent of at least 65537. II. Problem Description When verifying a PKCS#1 v1.5 signature, OpenSSL ignores any bytes which follow the cryptographic hash being signed. In a valid signature there will be no such bytes. III. Impact OpenSSL will incorrectly report some invalid signatures as valid. When an RSA public exponent of 3 is used, or more generally when a small public exponent is used with a relatively large modulus (e.g., a public exponent of 17 with a 4096-bit modulus), an attacker can construct a signature which OpenSSL will accept as a valid PKCS#1 v1.5 signature. IV. Workaround No workaround is available. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE, or to the RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, RELENG_5_3, or RELENG_4_11 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 4.11, 5.3, 5.4, 5.5, 6.0, and 6.1 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch http://security.FreeBSD.org/patches/SA-06:19/openssl.patch # fetch http://security.FreeBSD.org/patches/SA-06:19/openssl.patch.asc b) Execute the following commands as root: # cd /usr/src # patch /path/to/patch c) Recompile the operating system as described in URL: http://www.freebsd.org/handbook/makeworld.html and reboot the system. NOTE: Any third-party applications, including those installed from the FreeBSD ports collection, which are statically linked to libcrypto(3) should be recompiled in order to use the corrected code. VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - - RELENG_4 src/crypto/openssl/crypto/rsa/rsa_sign.c1.1.1.1.2.6 RELENG_4_11 src/UPDATING 1.73.2.91.2.22 src/sys/conf/newvers.sh 1.44.2.39.2.25 src/crypto/openssl/crypto/rsa/rsa_sign.c1.1.1.1.2.5.6.1 RELENG_5 src/crypto/openssl/crypto/rsa/rsa_sign.c1.1.1.6.4.1 RELENG_5_5 src/UPDATING 1.342.2.35.2.4 src/sys/conf/newvers.sh 1.62.2.21.2.6 src
