Allele Security Alert
ASA-2019-00649
Identifier(s)
ASA-2019-00649, CVE-2019-1551
Title
Overflow bug in the x86_64 Montgomery squaring procedure
Vendor(s)
The OpenSSL Project
Product(s)
OpenSSL
Affected version(s)
OpenSSL version 1.1.1
OpenSSL version 1.0.2
Fixed version(s)
OpenSSL version 1.1.1 with the following commit:
Fix an overflow bug in rsaz_512_sqr
https://github.com/openssl/openssl/commit/419102400a2811582a7a3d4a4e317d72e5ce0a8f
OpenSSL version 1.0.2 with the following commit:
Fix an overflow bug in rsaz_512_sqr
https://github.com/openssl/openssl/commit/f1c5eea8a817075d31e43f5876993c6710238c98
Proof of concept
Unknown
Description
There is an overflow bug in the x86_64 Montgomery squaring procedure used in exponentiation with 512-bit moduli. No EC algorithms are affected. Analysis suggests that attacks against 2-prime RSA1024, 3-prime RSA1536, and DSA1024 as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH512 are considered just feasible. However, for an attack the target would have to re-use the DH512 private key, which is not recommended anyway. Also applications directly using the low level API BN_mod_exp may be affected if they use BN_FLG_CONSTTIME.
Technical details
Unknown
Credits
Guido Vranken
Reference(s)
rsaz_512_sqr overflow bug on x86_64 (CVE-2019-1551)
https://mta.openssl.org/pipermail/openssl-announce/2019-December/000163.html
rsaz_512_sqr overflow bug on x86_64 (CVE-2019-1551)
https://www.openssl.org/news/secadv/20191206.txt
Fix an overflow bug in rsaz_512_sqr
https://github.com/openssl/openssl/commit/419102400a2811582a7a3d4a4e317d72e5ce0a8f
Fix an overflow bug in rsaz_512_sqr
https://github.com/openssl/openssl/commit/f1c5eea8a817075d31e43f5876993c6710238c98
Fix rsaz 512 overflow bug [1.1.1] #10575
https://github.com/openssl/openssl/pull/10575
Fix rsaz 512 overflow bug [1.0.2] #10576
https://github.com/openssl/openssl/pull/10576
https://people.canonical.com/~ubuntu-security/cve/CVE-2019-1551.html
CVE-2019-1551
https://security-tracker.debian.org/tracker/CVE-2019-1551
CVE-2019-1551
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-1551
CVE-2019-1551
https://nvd.nist.gov/vuln/detail/CVE-2019-1551
If there is any error in this alert or you wish a comprehensive analysis, let us know.
Last modified: December 6, 2019