CVE-2019-0053 Information

Description

Insufficient validation of environment variables in the telnet client supplied in Junos OS can lead to stack-based buffer overflows which can be exploited to bypass veriexec restrictions on Junos OS. A stack-based overflow is present in the handling of environment variables when connecting via the telnet client to remote telnet servers. This issue only affects the telnet client — accessible from the CLI or shell — in Junos OS. Inbound telnet services are not affected by this issue. This issue affects: Juniper Networks Junos OS: 12.3 versions prior to 12.3R12-S13; 12.3X48 versions prior to 12.3X48-D80; 14.1X53 versions prior to 14.1X53-D130 14.1X53-D49; 15.1 versions prior to 15.1F6-S12 15.1R7-S4; 15.1X49 versions prior to 15.1X49-D170; 15.1X53 versions prior to 15.1X53-D237 15.1X53-D496 15.1X53-D591 15.1X53-D69; 16.1 versions prior to 16.1R3-S11 16.1R7-S4; 16.2 versions prior to 16.2R2-S9; 17.1 versions prior to 17.1R3; 17.2 versions prior to 17.2R1-S8 17.2R2-S7 17.2R3-S1; 17.3 versions prior to 17.3R3-S4; 17.4 versions prior to 17.4R1-S6 17.4R2-S3 17.4R3; 18.1 versions prior to 18.1R2-S4 18.1R3-S3; 18.2 versions prior to 18.2R1-S5 18.2R2-S2 18.2R3; 18.2X75 versions prior to 18.2X75-D40; 18.3 versions prior to 18.3R1-S3 18.3R2; 18.4 versions prior to 18.4R1-S2 18.4R2.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Reference

http://packetstormsecurity.com/files/153746/FreeBSD-Security-Advisory-FreeBSD-SA-19-12.telnet.html https://kb.juniper.net/JSA10947 https://seclists.org/bugtraq/2019/Jul/45 https://security.FreeBSD.org/advisories/FreeBSD-SA-19:12.telnet.asc https://www.exploit-db.com/exploits/45982

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.8