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computer vulnerability alert CVE-2015-2808

TLS: RC4 decryption via Bar Mitzvah

Synthesis of the vulnerability

An attacker can use the Bar Mitzvah Attack on TLS, in order to obtain sensitive information encrypted by RC4.
Impacted software: DCFM Enterprise, Brocade Network Advisor, Brocade vTM, Avamar, Black Diamond, ExtremeXOS, Summit, BIG-IP Hardware, TMOS, HPE BSM, HP Data Protector, HPE NNMi, HP Operations, SiteScope, HP Switch, HP-UX, AIX, DB2 UDB, Domino, Notes, IRAD, Security Directory Server, Tivoli Storage Manager, Tivoli Workload Scheduler, WebSphere AS Traditional, WebSphere MQ, SnapManager, Oracle Communications, Oracle Directory Server, Oracle Directory Services Plus, Oracle Fusion Middleware, Oracle GlassFish Server, Oracle Identity Management, Oracle iPlanet Web Server, Oracle OIT, Oracle Virtual Directory, WebLogic, Oracle Web Tier, SSL protocol, RHEL, SUSE Linux Enterprise Desktop, SLES.
Severity of this computer vulnerability: 2/4.
Consequences of a hack: data reading.
Attacker's origin: internet client.
Creation date: 27/03/2015.
Références of this announce: 1450666, 1610582, 1647054, 1882708, 1883551, 1883553, 1902260, 1903541, 1960659, 1963275, 1967498, 523628, 7014463, 7022958, 7045736, 9010041, 9010044, Bar Mitzvah, BSA-2015-007, c04708650, c04767175, c04770140, c04772305, c04773119, c04773241, c04777195, c04777255, c04832246, c04926789, c05085988, c05336888, cpujan2018, cpuoct2017, CVE-2015-2808, DSA-2018-124, HPSBGN03350, HPSBGN03393, HPSBGN03399, HPSBGN03407, HPSBGN03414, HPSBGN03415, HPSBGN03580, HPSBHF03673, HPSBMU03345, HPSBMU03401, HPSBUX03435, HPSBUX03512, NTAP-20150715-0001, NTAP-20151028-0001, RHSA-2015:1020-01, RHSA-2015:1021-01, RHSA-2015:1091-01, SOL16864, SSRT102254, SSRT102977, SUSE-SU-2015:1073-1, SUSE-SU-2015:1085-1, SUSE-SU-2015:1086-1, SUSE-SU-2015:1086-2, SUSE-SU-2015:1086-3, SUSE-SU-2015:1086-4, SUSE-SU-2015:1138-1, SUSE-SU-2015:1161-1, VIGILANCE-VUL-16486, VN-2015-004.

Description of the vulnerability

During the initialization of a TLS session, the client and the server negotiate cryptographic algorithms. The RC4 algorithm can be chosen to encrypt data.

For some weak keys (one over 2^24), the Invariance Weakness can be used to predict the two LSB (Least Significant Bit) of the 100 first bytes encrypted with RC4. The first TLS message is "Finished" (36 bytes), thus an attacker can predict LSBs of 64 bytes.

An attacker can therefore use the Bar Mitzvah Attack on TLS, in order to obtain sensitive information encrypted by RC4.
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