8.1
HIGH
CVE-2021-34718
Cisco SSH Server File Overwrite and Read Vulnerability
Description

A vulnerability in the SSH Server process of Cisco IOS XR Software could allow an authenticated, remote attacker to overwrite and read arbitrary files on the local device. This vulnerability is due to insufficient input validation of arguments that are supplied by the user for a specific file transfer method. An attacker with lower-level privileges could exploit this vulnerability by specifying Secure Copy Protocol (SCP) parameters when authenticating to a device. A successful exploit could allow the attacker to elevate their privileges and retrieve and upload files on a device that they should not have access to.

INFO

Published Date :

Sept. 9, 2021, 5:15 a.m.

Last Modified :

Nov. 21, 2024, 6:11 a.m.

Remotely Exploitable :

Yes !

Impact Score :

5.2

Exploitability Score :

2.8
Affected Products

The following products are affected by CVE-2021-34718 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Cisco ios_xr
2 Cisco asr_9001
3 Cisco asr_9006
4 Cisco asr_9010
5 Cisco asr_9904
6 Cisco asr_9912
7 Cisco asr_9922
8 Cisco ncs_1001
9 Cisco ncs_1002
10 Cisco ncs_1004
11 Cisco ncs_5001
12 Cisco ncs_5002
13 Cisco ncs_5501-se
14 Cisco ncs_5502-se
15 Cisco ncs_5508
16 Cisco ncs_5516
17 Cisco asr_9901
18 Cisco asr_9902
19 Cisco asr_9903
20 Cisco asr_9906
21 Cisco asr_9910
22 Cisco ncs_5011
23 Cisco ncs_520
24 Cisco ncs_540
25 Cisco ncs_5501
26 Cisco ncs_5502
27 Cisco ncs_6008
28 Cisco ncs_6000
29 Cisco ios_xrv_9000
30 Cisco ncs_4009
31 Cisco ncs_4016
32 Cisco asr_9000v-v2
33 Cisco ios_xrv
34 Cisco ncs_540_fronthaul
35 Cisco ncs_560-4
36 Cisco ncs_560-7
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-34718.

URL Resource
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2 Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2 Vendor Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-34718 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-34718 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Removed CVSS V3 Cisco Systems, Inc. AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
    Added CVSS V3.1 Cisco Systems, Inc. AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
  • Initial Analysis by [email protected]

    Sep. 21, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:S/C:C/I:C/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
    Changed Reference Type https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2 No Types Assigned https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2 Vendor Advisory
    Added CWE NIST CWE-88
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions up to (excluding) 7.3.2 *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:asr_9000v-v2:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9001:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9006:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9010:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9901:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9902:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9903:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9904:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9906:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9910:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9912:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:asr_9922:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions up to (excluding) 7.3.2 *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ios_xrv:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ios_xrv_9000:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions up to (excluding) 7.3.2 *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_520:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_540:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_540_fronthaul:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_560-4:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_560-7:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions up to (excluding) 7.3.2 *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_5001:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_5002:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_5011:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions up to (excluding) 7.3.2 *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_4009:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_4016:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions up to (excluding) 7.3.2 *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_5501:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_5501-se:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_5502:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_5502-se:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_5508:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_5516:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions up to (excluding) 7.3.2 *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_6000:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_6008:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions up to (excluding) 7.3.2 *cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_1001:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_1002:-:*:*:*:*:*:*:* cpe:2.3:h:cisco:ncs_1004:-:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Sep. 09, 2021

    Action Type Old Value New Value
    Changed Description A vulnerability in the SSH Server process of Cisco IOS XR Software could allow an authenticated, remote attacker to overwrite and read arbitrary files on the local device. This vulnerability is due to insufficient input validation of arguments that are supplied by the user for a specific file transfer method. An attacker with lower-level privileges could exploit this vulnerability by specifying Secure Copy Protocol (SCP) parameters when authenticating to a device. A successful exploit could allow the attacker to elevate their privileges and retrieve and upload files on a device that they should not have access to. A vulnerability in the SSH Server process of Cisco IOS XR Software could allow an authenticated, remote attacker to overwrite and read arbitrary files on the local device. This vulnerability is due to insufficient input validation of arguments that are supplied by the user for a specific file transfer method. An attacker with lower-level privileges could exploit this vulnerability by specifying Secure Copy Protocol (SCP) parameters when authenticating to a device. A successful exploit could allow the attacker to elevate their privileges and retrieve and upload files on a device that they should not have access to.
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-34718 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.17 }} 0.07%

score

0.53859

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability