2017-01 Security Bulletin: Network and Security Manager (NSM): Multiple OpenSSH vulnerabilities affect NSM Appliance OS.Product Affected:NSM Appliances (NSM3000, NSM4000 and NSMExpress).
Multiple OpenSSH software vulnerabilities affect NSM Appliance OS.
OpenSSH software package is updated in the NSM Appliance OS gzip upgrade package v3 based on CentOS 6.
Important security issues resolved as a result of this upgrade include,
CVSS base score
The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through 6.9 does not properly restrict the processing of keyboard-interactive devices within a single connection, which makes it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list.
sshd in OpenSSH 6.8 and 6.9 uses world-writable permissions for TTY devices, which allows local users to cause a denial of service (terminal disruption) or possibly have unspecified other impact by writing to a device, as demonstrated by writing an escape sequence.
The do_setup_env function in session.c in sshd in OpenSSH through 7.2p2, when the UseLogin feature is enabled and PAM is configured to read .pam_environment files in user home directories, allows local users to gain privileges by triggering a crafted environment for the /bin/login program, as demonstrated by an LD_PRELOAD environment variable.
Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH before 7.0 on non-OpenBSD platforms might allow local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request.
Multiple CRLF injection vulnerabilities in session.c in sshd in OpenSSH before 7.2p2 allow remote authenticated users to bypass intended shell-command restrictions via crafted X11 forwarding data, related to the (1) do_authenticated1 and (2) session_x11_req functions.
The (1) roaming_read and (2) roaming_write functions in roaming_common.c in the client in OpenSSH 5.x, 6.x, and 7.x before 7.1p2, when certain proxy and forward options are enabled, do not properly maintain connection file descriptors, which allows remote servers to cause a denial of service (heap-based buffer overflow) or possibly have unspecified other impact by requesting many forwardings.
The x11_open_helper function in channels.c in ssh in OpenSSH before 6.9, when ForwardX11Trusted mode is not used, lacks a check of the refusal deadline for X connections, which makes it easier for remote attackers to bypass intended access restrictions via a connection outside of the permitted time window.
The resend_bytes function in roaming_common.c in the client in OpenSSH 5.x, 6.x, and 7.x before 7.1p2 allows remote servers to obtain sensitive information from process memory by requesting transmission of an entire buffer, as demonstrated by reading a private key.
The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c.
Please refer to JSA10759 for a list of OpenSSL vulnerabilities resolved.Juniper SIRT is not aware of any malicious exploitation of these vulnerabilities on NSM Appliances.
All these issues are resolved in NSM Appliance Upgrade Package v3 based on CentOS 6 (pending release, expected to be available before end of January 2017).
This issue is being tracked as PR 1181267 and is visible on the Customer Support website.
Workaround:Use access lists or firewall filters to limit access to the NSM Appliance only from trusted hosts.
NSM Maintenance Releases are available at http://www.juniper.net/support/downloads/?p=nsm#sw.
2017-01-11: Initial release.
Related Links:CVSS Score:8.1 (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)
Risk Assessment:Considering the highest score of 8.1 from CVE-2016-0778.