cbcvebase.
CVE-2017-6736
published 2017-07-17

CVE-2017-6736: The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow an authenticated…

PriorityP191high8.8CVSS 3.1
AVNACLPRLUINSUCHIHAH
KEVITWEXPLOIT
CISA Known Exploited Vulnerabilitydue 2022-03-24
Exploited in the wild
EPSS
70.56%
99.3th percentile
The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload. An attacker could exploit these vulnerabilities by sending a crafted SNMP packet to an affected system via IPv4 or IPv6. Only traffic directed to an affected system can be used to exploit these vulnerabilities. The vulnerabilities are due to a buffer overflow condition in the SNMP subsystem of the affected software. The vulnerabilities affect all versions of SNMP - Versions 1, 2c, and 3. To exploit these vulnerabilities via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for the affected system. To exploit these vulnerabilities via SNMP Version 3, the attacker must have user credentials for the affected system. A successful exploit could allow the attacker to execute arbitrary code and obtain full control of the affected system or cause the affected system to reload. Customers are advised to apply the workaround as contained in the Workarounds section below. Fixed software information is available via the Cisco IOS Software Checker. All devices that have enabled SNMP and have not explicitly excluded the affected MIBs or OIDs should be considered vulnerable. There are workarounds that address these vulnerabilities.

Affected

1781 ranges· showing 25
VendorProductVersion rangeFixed in
ciscoios
ciscoios
ciscoios
ciscoios
ciscoios
ciscoios
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ciscoios
ciscoios
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ciscoios
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ciscoios

Detection & IOCsextracted from sources · hover to see the quote

portUDP/161
otherOID: 1.3.6.1.4.1.9.9.95.1.3.1.1.7.108.39.84.85.195.249.106.59.210.37.23.42.103.182.75.232.81{0}{1}{2}{3}{4}{5}{6}{7}.14.167.142.47.118.77.96.179.109.211.170.27.243.88.157.50{8}{9}.35.27.203.165.44.25.83.68.39.22.219.77.32.38.6.115{10}{11}.11.187.147.166.116.171.114.126.109.248.144.111.30
commandsnmpget -v 2c -c public 192.168.88.1 1.3.6.1.2.1.1.1.0
versionCisco IOS Software, 2800 Software (C2800NM-ADVENTERPRISEK9-M), Version 15.1(4)M12a, RELEASE SOFTWARE (fc1)
bytes
shellcode_start: \x80\x00\xf0\x00 (write address 0x8000f000)
bytes
Shellcode: 8fb40250000000003c163e2936d655b026d620000000000002d4a821000000008eb60000000000003c1480003694f000ae96000000000000aea00000000000003c1fbfc437ff89a803e0000800000000
bytes
Unset shellcode: 8fb40250000000003c163e2936d655b026d620000000000002d4a821000000003c1480003694f0008e96000000000000aeb60000000000003c1fbfc437ff89a803e0000800000000
  • Detect exploit by monitoring for SNMP GET requests over UDP/161 containing the ALPS MIB OID prefix 1.3.6.1.4.1.9.9.95.1.3.1.1.7 with anomalously long OID strings carrying embedded binary-encoded data segments.
  • All SNMP-enabled Cisco IOS/IOS XE devices that have not explicitly excluded the affected MIBs or OIDs should be considered vulnerable; audit SNMP ACLs and restrict access to trusted management hosts.
  • Exploitation is possible via SNMP v1, v2c, and v3; monitor for SNMP traffic from unexpected sources regardless of SNMP version in use.
  • ·The PoC exploit is firmware-specific and only confirmed to work against Cisco ISR 2811 running a specific firmware version; other platforms/versions may require different offsets.
  • ·Exploitation via SNMPv2c or earlier requires knowledge of the read-only community string; exploitation via SNMPv3 requires valid user credentials — unauthenticated exploitation is not possible.
  • ·Only traffic directed to the affected system can be used to exploit these vulnerabilities; transit SNMP traffic does not trigger the bug.

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv3.08.8HIGHCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.09.0CRITICALAV:N/AC:L/Au:S/C:C/I:C/A:C
vulncheck8.8HIGH
cisa8.8HIGH
vendor_cisco8.8HIGH
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