ZeroHour

CVE-2020-1631

KEVlarge

Unauthenticated Path Traversal/LFI in Juniper Junos OS HTTP/HTTPS Service

CISA: Juniper Junos OS Path Traversal Vulnerability

CVSS 3.1
9.8 critical
EPSS
5%p91
Published
()
KEV added
AI analysis

CVE-2020-1631 is a path traversal and local file inclusion flaw in the HTTP/HTTPS service (httpd) used by J-Web, Web Authentication, Dynamic-VPN, Firewall Authentication Pass-Through with Web-Redirect, and Zero Touch Provisioning in Juniper Junos OS. An unauthenticated network attacker sends crafted requests to any enabled HTTP/HTTPS service and can inject commands into httpd.log (limited, since the service runs as user 'nobody'), read world-readable files—including the device configuration file on Junos 19.3R1 and above—or obtain J-Web session tokens. If J-Web is enabled, the attacker can hijack an active session and inherit that user's access, gaining administrator privileges to J-Web if an administrator is logged in (up to CVSS 8.8; the dashboard rates the worst case 9.8). Only Junos devices with HTTP/HTTPS services enabled are affected; the advisory's version range begins with Junos OS 12.3 prior to 12.3R12 (the source text is truncated). Juniper SIRT received a single report of exploitation in the wild, the flaw is on CISA's Known Exploited Vulnerabilities catalog (added 2022-03-25), and EPSS estimates a 4.7% chance of exploitation in the next 30 days (91st percentile).

What to do: Upgrade Junos OS per Juniper's advisory (at minimum past the 12.3R12 boundary given in the affected range; consult Juniper for fixed releases on other branches). As mitigation, disable J-Web/HTTP(S) management services where not needed or restrict access with firewall filters/ACLs. Hunt for compromise by searching /var/log/httpd.log (and rotated httpd.log.0.gz/.1.gz) for the patterns "=*;*&" or "=*%3b*&", keeping in mind a skilled attacker may have removed these entries.

Affected
Juniper Networks Junos OS12.3 versions prior to 12.3R12 (advisory version list truncated in source; only devices with HTTP/HTTPS services enabled are affected; config-file exposure note
Estimated exposure
largetens of thousands of internet-exposed Junos devices with HTTP/HTTPS (J-Web or related web services) enabled — The Junos install base is very large across enterprise and service-provider networks, but only devices exposing the HTTP/HTTPS management services are vulnerable, and public internet scans typically show tens of thousands of Juniper…

Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.

Description

A vulnerability in the HTTP/HTTPS service used by J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Zero Touch Provisioning (ZTP) allows an unauthenticated attacker to perform local file inclusion (LFI) or path traversal. Using this vulnerability, an attacker may be able to inject commands into the httpd.log, read files with 'world' readable permission file or obtain J-Web session tokens. In the case of command injection, as the HTTP service runs as user 'nobody', the impact of this command injection is limited. (CVSS score 5.3, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) In the case of reading files with 'world' readable permission, in Junos OS 19.3R1 and above, the unauthenticated attacker would be able to read the configuration file. (CVSS score 5.9, vector CVSS:3.1/ AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N) If J-Web is enabled, the attacker could gain the same level of access of anyone actively logged into J-Web. If an administrator is logged in, the attacker could gain administrator access to J-Web. (CVSS score 8.8, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) This issue only affects Juniper Networks Junos OS devices with HTTP/HTTPS services enabled. Junos OS devices with HTTP/HTTPS services disabled are not affected. If HTTP/HTTPS services are enabled, the following command will show the httpd processes: user@device> show system processes | match http 5260 - S 0:00.13 /usr/sbin/httpd-gk -N 5797 - I 0:00.10 /usr/sbin/httpd --config /jail/var/etc/httpd.conf To summarize: If HTTP/HTTPS services are disabled, there is no impact from this vulnerability. If HTTP/HTTPS services are enabled and J-Web is not in use, this vulnerability has a CVSS score of 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N). If J-Web is enabled, this vulnerability has a CVSS score of 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). Juniper SIRT has received a single report of this vulnerability being exploited in the wild. Out of an abundance of caution, we are notifying customers so they can take appropriate actions. Indicators of Compromise: The /var/log/httpd.log may have indicators that commands have injected or files being accessed. The device administrator can look for these indicators by searching for the string patterns "=*;*&" or "*%3b*&" in /var/log/httpd.log, using the following command: user@device> show log httpd.log | match "=*;*&|=*%3b*&" If this command returns any output, it might be an indication of malicious attempts or simply scanning activities. Rotated logs should also be reviewed, using the following command: user@device> show log httpd.log.0.gz | match "=*;*&|=*%3b*&" user@device> show log httpd.log.1.gz | match "=*;*&|=*%3b*&" Note that a skilled attacker would likely remove these entries from the local log file, thus effectively eliminating any reliable signature that the device had been attacked. This issue affects Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S16; 12.3X48 versions prior to 12.3X48-D101, 12.3X48-D105; 14.1X53 versions prior to 14.1X53-D54; 15.1 versions prior to 15.1R7-S7; 15.1X49 versions prior to 15.1X49-D211, 15.1X49-D220; 16.1 versions prior to 16.1R7-S8; 17.2 versions prior to 17.2R3-S4; 17.3 versions prior to 17.3R3-S8; 17.4 versions prior to 17.4R2-S11, 17.4R3-S2; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S4; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R1-S7, 18.4R3-S2 ; 18.4 version 18.4R2 and later versions; 19.1 versions prior to 19.1R1-S5, 19.1R3-S1; 19.1 version 19.1R2 and later versions; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2; 20.1 versions prior to 20.1R1-S1, 20.1R2.

CISA Known Exploited Vulnerability
Affected
Juniper Junos OS
Required action
Apply updates per vendor instructions.
Due date
Ransomware use
Unknown
Vendors
juniper
Products
junos
Weakness
CWE-22, CWE-73
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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