Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2019.1752
Cisco Small Business Series Switches Simple Network
Management Protocol Denial of Service Vulnerability
16 May 2019
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco Small Business Series Switches
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2019-1814 CVE-2019-1806
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-sb-snmpdos
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-sb300sms-dhcp
Comment: This bulletin contains two (2) Cisco Systems security advisories.
- --------------------------BEGIN INCLUDED TEXT--------------------
Cisco Small Business Series Switches Simple Network Management Protocol Denial
of Service Vulnerability
Priority: High
Advisory ID: cisco-sa-20190515-sb-snmpdos
First Published: 2019 May 15 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds availableCisco Bug IDs: CSCvn49346CSCvn93730
CVE-2019-1806
CWE-20
CVSS Score:
7.7 AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
Summary
o A vulnerability in the Simple Network Management Protocol (SNMP) input
packet processor of Cisco Small Business Sx200, Sx300, Sx500, ESW2 Series
Managed Switches and Small Business Sx250, Sx350, Sx550 Series Switches
could allow an authenticated, remote attacker to cause the SNMP application
of an affected device to cease processing traffic, resulting in the CPU
utilization reaching one hundred percent. Manual intervention may be
required before a device resumes normal operations.
The vulnerability is due to improper validation of SNMP protocol data units
(PDUs) in SNMP packets. An attacker could exploit this vulnerability by
sending a malicious SNMP packet to an affected device. A successful exploit
could allow the attacker to cause the device to cease forwarding traffic,
which could result in a denial of service (DoS) condition.
Cisco has released firmware updates that address this vulnerability. There
are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
cisco-sa-20190515-sb-snmpdos
Affected Products
o Vulnerable Products
This vulnerability affects the following Cisco products if they are running
a vulnerable firmware release:
Small Business Sx200, Sx300, Sx500, ESW2 Series Managed Switches
Small Business Sx250, Sx350, Sx550 Series Switches
Refer to the Cisco product release notes for the complete list of
vulnerable product models: Release Notes for 200, 300, 500, and ESW2 Series
Switches and Release Notes for SF250, SG250, SF350, SG350/350X/350XG,
SF550X, SG550X/ 550XG, SX350X, SX550X Series Switches .
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Indicators of Compromise
o The device may cease to forward traffic, or the CPU utilization could spike
to one hundred percent. When the device is in this state, the Out of Band
(OOB) interface may still be responsive and the device could still respond
to further SNMP requests. The device may need to be reloaded manually to
restore service.
Contact the Cisco Technical Assistance Center (TAC) for further assistance.
Workarounds
o There are no workarounds that address this vulnerability.
Fixed Software
o Cisco has released free software updates that address the vulnerability
described in this advisory. Customers may only install and expect support
for software versions and feature sets for which they have purchased a
license. By installing, downloading, accessing, or otherwise using such
software upgrades, customers agree to follow the terms of the Cisco
software license: https://www.cisco.com/c/en/us/products/
end-user-license-agreement.html
Additionally, customers may only download software for which they have a
valid license, procured from Cisco directly, or through a Cisco authorized
reseller or partner. In most cases this will be a maintenance upgrade to
software that was previously purchased. Free security software updates do
not entitle customers to a new software license, additional software
feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories and Alerts page , to determine exposure and a
complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service
contract and customers who make purchases through third-party vendors but
are unsuccessful in obtaining fixed software through their point of sale
should obtain upgrades by contacting the Cisco TAC:
https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared
to provide the URL of this advisory as evidence of entitlement to a free
upgrade.
Fixed Releases
Customers are advised to upgrade to an appropriate fixed software release
as indicated in the following table:
Cisco Product First Fixed Release for This
Vulnerability
Small Business Sx200, Sx300, Sx500, ESW2 1.4.10.6
Series Managed Switches
Small Business Sx250, Sx350, Sx550 Series 2.5.0.78
Switches
The firmware can be downloaded from the Software Center on Cisco.com by
navigating to Downloads Home > Products > Switches > LAN Switches - Small
Business and selecting the respective model.
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any public announcements or malicious use of the vulnerability that is
described in this advisory.
Source
o Cisco would like to thank Patrick S. Stuckenberger of August Manser AG for
reporting this vulnerability.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy . This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
cisco-sa-20190515-sb-snmpdos
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2019-May-15 |
+----------+---------------------------+----------+--------+--------------+
- -------------------------------------------------------------------------------
Cisco Small Business 300 Series Managed Switches DHCP Denial of Service
Vulnerability
Priority: Medium
Advisory ID: cisco-sa-20190515-sb300sms-dhcp
First Published: 2019 May 15 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds availableCisco Bug IDs: CSCvn17215
CVE-2019-1814
CWE-400
CVSS Score:
6.8 AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
Summary
o A vulnerability in the interactions between the DHCP and TFTP features for
Cisco Small Business 300 Series (Sx300) Managed Switches could allow an
unauthenticated, remote attacker to cause the device to become low on
system memory, which in turn could lead to an unexpected reload of the
device and result in a denial of service (DoS) condition on an affected
device.
The vulnerability is due to a failure to free system memory when an
unexpected DHCP request is received. An attacker could exploit this
vulnerability by sending a crafted DHCP packet to the targeted device. A
successful exploit could allow the attacker to cause an unexpected reload
of the device.
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
cisco-sa-20190515-sb300sms-dhcp
Affected Products
o Vulnerable Products
This vulnerability affects Cisco Small Business 300 Series (Sx300) Managed
Switches in all prior firmware releases until the first fixed release if
the device is configured to boot via DHCP but not TFTP.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Workarounds
o There are no workarounds that address this vulnerability.
Fixed Software
o For information about fixed software releases , consult the Cisco bug ID(s)
at the top of this advisory.
When considering software upgrades, customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories and Alerts page , to determine exposure and a
complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
providers.
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any public announcements or malicious use of the vulnerability that is
described in this advisory.
Source
o Cisco would like to thank Daniel O'Connor from Genesis Software for
reporting this vulnerability.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy . This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
cisco-sa-20190515-sb300sms-dhcp
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2019-May-15 |
+----------+---------------------------+----------+--------+--------------+
- --------------------------END INCLUDED TEXT--------------------
You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.
NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
https://www.auscert.org.au/bulletins/
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967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=++rM
-----END PGP SIGNATURE-----