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FreeBSD : PuTTY -- memory corruption in terminal emulator's erase character handling (0cb0afd9-86b8-11e5-bf60-080027ef73ec)

medium Nessus Plugin ID 86805

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Synopsis

The remote FreeBSD host is missing a security-related update.

Description

Ben Harris reports :

Versions of PuTTY and pterm between 0.54 and 0.65 inclusive have a potentially memory-corrupting integer overflow in the handling of the ECH (erase characters) control sequence in the terminal emulator.

To exploit a vulnerability in the terminal emulator, an attacker must be able to insert a carefully crafted escape sequence into the terminal stream. For a PuTTY SSH session, this must be before encryption, so the attacker likely needs access to the server you're connecting to. For instance, an attacker on a multi-user machine that you connect to could trick you into running cat on a file they control containing a malicious escape sequence. (Unix write(1) is not a vector for this, if implemented correctly.)

Only PuTTY, PuTTYtel, and pterm are affected; other PuTTY tools do not include the terminal emulator, so cannot be exploited this way.

Solution

Update the affected package.

See Also

http://www.nessus.org/u?4f64de2b

http://www.nessus.org/u?1c947aa0

Plugin Details

Severity: Medium

ID: 86805

File Name: freebsd_pkg_0cb0afd986b811e5bf60080027ef73ec.nasl

Version: 2.6

Type: local

Published: 11/10/2015

Updated: 1/6/2021

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:putty, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Patch Publication Date: 11/9/2015

Vulnerability Publication Date: 11/6/2015

Reference Information

CVE: CVE-2015-5309