Attack vector
NETWORK Attack complexity
MEDIUM Privileges required
NONE Confidentiality impact
NONE Integrity impact
NONE Availability impact
COMPLETE Published: 2018-01-10
Updated: 2019-10-09
Summary
A sustained sequence of different types of normal transit traffic can trigger a high CPU consumption denial of service condition in the Junos OS register and schedule software interrupt handler subsystem when a specific command is issued to the device. This affects one or more threads and conversely one or more running processes running on the system. Once this occurs, the high CPU event(s) affects either or both the forwarding and control plane. As a result of this condition the device can become inaccessible in either or both the control and forwarding plane and stops forwarding traffic until the device is rebooted. The issue will reoccur after reboot upon receiving further transit traffic. Score: 5.7 MEDIUM (CVSS:3.0/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) For network designs utilizing layer 3 forwarding agents or other ARP through layer 3 technologies, the score is slightly higher. Score: 6.5 MEDIUM (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) If the following entry exists in the RE message logs then this may indicate the issue is present. This entry may or may not appear when this issue occurs. /kernel: Expensive timeout(9) function: Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D50; 12.3X48 versions prior to 12.3X48-D30; 12.3R versions prior to 12.3R12-S7; 14.1 versions prior to 14.1R8-S4, 14.1R9; 14.1X53 versions prior to 14.1X53-D30, 14.1X53-D34; 14.2 versions prior to 14.2R8; 15.1 versions prior to 15.1F6, 15.1R3; 15.1X49 versions prior to 15.1X49-D40; 15.1X53 versions prior to 15.1X53-D31, 15.1X53-D33, 15.1X53-D60. No other Juniper Networks products or platforms are affected by this issue.
Vulnerable Configurations
| Part | Description | Count |
| OS | Juniper | 76 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- XML Ping of the Death
An attacker initiates a resource depletion attack where a large number of small XML messages are delivered at a sufficiently rapid rate to cause a denial of service or crash of the target. Transactions such as repetitive SOAP transactions can deplete resources faster than a simple flooding attack because of the additional resources used by the SOAP protocol and the resources necessary to process SOAP messages. The transactions used are immaterial as long as they cause resource utilization on the target. In other words, this is a normal flooding attack augmented by using messages that will require extra processing on the target.
- XML Entity Expansion
An attacker submits an XML document to a target application where the XML document uses nested entity expansion to produce an excessively large output XML. XML allows the definition of macro-like structures that can be used to simplify the creation of complex structures. However, this capability can be abused to create excessive demands on a processor's CPU and memory. A small number of nested expansions can result in an exponential growth in demands on memory.
- Inducing Account Lockout
An attacker leverages the security functionality of the system aimed at thwarting potential attacks to launch a denial of service attack against a legitimate system user. Many systems, for instance, implement a password throttling mechanism that locks an account after a certain number of incorrect log in attempts. An attacker can leverage this throttling mechanism to lock a legitimate user out of their own account. The weakness that is being leveraged by an attacker is the very security feature that has been put in place to counteract attacks.
- Violating Implicit Assumptions Regarding XML Content (aka XML Denial of Service (XDoS))
XML Denial of Service (XDoS) can be applied to any technology that utilizes XML data. This is, of course, most distributed systems technology including Java, .Net, databases, and so on. XDoS is most closely associated with web services, SOAP, and Rest, because remote service requesters can post malicious XML payloads to the service provider designed to exhaust the service provider's memory, CPU, and/or disk space. The main weakness in XDoS is that the service provider generally must inspect, parse, and validate the XML messages to determine routing, workflow, security considerations, and so on. It is exactly these inspection, parsing, and validation routines that XDoS targets. There are three primary attack vectors that XDoS can navigate Target CPU through recursion: attacker creates a recursive payload and sends to service provider Target memory through jumbo payloads: service provider uses DOM to parse XML. DOM creates in memory representation of XML document, but when document is very large (for example, north of 1 Gb) service provider host may exhaust memory trying to build memory objects. XML Ping of death: attack service provider with numerous small files that clog the system. All of the above attacks exploit the loosely coupled nature of web services, where the service provider has little to no control over the service requester and any messages the service requester sends.
Nessus
| NASL family | Junos Local Security Checks |
| NASL id | JUNIPER_JSA10832.NASL |
| description | According to its self-reported version number, the remote Junos device is affected by a denial of service vulnerability. |
| last seen | 2020-06-01 |
| modified | 2020-06-02 |
| plugin id | 106389 |
| published | 2018-01-26 |
| reporter | This script is Copyright (C) 2018 Tenable Network Security, Inc. |
| source | https://www.tenable.com/plugins/nessus/106389 |
| title | Juniper Junos Kernel Register and Schedule Software Interrupt Handler Subsystem CPU Consumption Remote DoS (JSA10832) |