Allele Security Alert
ASA-2019-00467
Identifier(s)
ASA-2019-00467, CVE-2019-0053, FreeBSD-SA-19:12.telnet
Title
telnet client multiple vulnerabilities
Vendor(s)
The FreeBSD Project
Product(s)
FreeBSD
Affected version(s)
All supported versions of FreeBSD
Fixed version(s)
2019-07-19 15:37:29 UTC (stable/12, 12.0-STABLE)
2019-07-24 12:51:52 UTC (releng/12.0, 12.0-RELEASE-p8)
2019-07-19 15:27:53 UTC (stable/11, 11.2-STABLE)
2019-07-24 12:51:52 UTC (releng/11.2, 11.2-RELEASE-p12)
2019-07-24 12:51:52 UTC (releng/11.3, 11.3-RELEASE-p1)
Proof of concept
Unknown
Description
Insufficient validation of environment variables in the telnet client supplied in FreeBSD can lead to stack-based buffer overflows. 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. Inbound telnet sessions to telnetd(8) are not affected by this issue.
These buffer overflows may be triggered when connecting to a malicious server, or by an active attacker in the network path between the client and server. Specially crafted TELNET command sequences may cause the execution of arbitrary code with the privileges of the user invoking telnet(1).
Technical details
Unknown
Workaround
Do not use telnet(1) to connect to untrusted machines or over an untrusted network.
Credits
Juniper Networks
Reference(s)
FreeBSD-SA-19:12.telnet
https://www.freebsd.org/security/advisories/FreeBSD-SA-19:12.telnet.asc
telnet.patch
https://security.FreeBSD.org/patches/SA-19:12/telnet.patch
telnet: fix a couple of snprintf() buffer overflows
https://svnweb.freebsd.org/base?view=revision&revision=r350139
Fix multiple telnet client vulnerabilities.
https://svnweb.freebsd.org/base?view=revision&revision=r350281
telnet: fix a couple of snprintf() buffer overflows
https://svnweb.freebsd.org/base?view=revision&revision=r350140
CVE-2019-0053
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-0053
CVE-2019-0053
https://nvd.nist.gov/vuln/detail/CVE-2019-0053
If there is any error in this alert or you wish a comprehensive analysis, let us know.
Last modified: August 1, 2019