PT-2015-5409 · Microsoft · Schannel+1

Published 2015-03-06 · Updated 2021-04-07 · CVE-2015-1637

Positive Technologies (AI Summary)

CVSS v2.0

4.3

Medium

Base vector

AV:N/AC:M/Au:N/C:N/I:P/A:N

Name of the Vulnerable Software and Affected Versions Secure Channel (Schannel) (affected versions not specified)

Description A security feature bypass issue exists due to a problem in the TLS state machine, where a client system accepts an RSA key with a shorter key length than the originally negotiated key length. This issue facilitates exploitation of the FREAK technique, allowing an attacker to downgrade the key length of an RSA key to EXPORT-grade length in an encrypted TLS session during a man-in-the-middle (MiTM) attack. The attacker could then intercept and decrypt this traffic.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Weakness Enumeration

CWE-310

Related Identifiers

CVE-2015-1637

Affected Products

Schannel

Windows

References · 10

• https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-031 · Vendor Advisory
• https://technet.microsoft.com/library/security/3046015 · Vendor Advisory
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1637 · Security Note
• https://freakattack.com · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2015-1637 · Security Note
• http://web.archive.org/web/20150321220028/https://freakattack.com · Note
• http://securityfocus.com/bid/72965 · Note
• https://t.me/cvenotify/12853 · Telegram Post
• http://technet.microsoft.com/security/bulletin/ms15-031 · Note
• http://securitytracker.com/id/1031833 · Note