Vulnerabilities > CVE-2017-3733 - Improper Input Validation vulnerability in multiple products

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
openssl
hp
CWE-20
nessus
NVD
Published: 2017-05-04
Updated: 2019-04-23

Summary

During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.

Vulnerable Configurations

Part Description Count
Application
Openssl
5
Application
Hp
2

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

Nessus

  • NASL familyWeb Servers
    NASL idOPENSSL_1_1_0E.NASL
    descriptionAccording to its banner, the version of OpenSSL running on the remote host is 1.1.0 prior to 1.1.0e. It is, therefore, affected by a denial of service vulnerability that is triggered during a renegotiation handshake in which the Encrypt-Then-Mac extension is negotiated when it was not in the original handshake or vice-versa. An unauthenticated, remote attacker can exploit this issue to cause OpenSSL to crash, depending on which cipher suite is being used. Note that both clients and servers are affected.
    last seen2020-06-01
    modified2020-06-02
    plugin id97328
    published2017-02-23
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/97328
    titleOpenSSL 1.1.0 < 1.1.0e Encrypt-Then-Mac Extension DoS
    code
    #
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(97328);
  script_version("1.6");
  script_cvs_date("Date: 2019/11/13");

  script_cve_id("CVE-2017-3733");

  script_name(english:"OpenSSL 1.1.0 < 1.1.0e Encrypt-Then-Mac Extension DoS");
  script_summary(english:"Performs a banner check.");

  script_set_attribute(attribute:"synopsis", value:
"A service running on the remote host is affected by a denial of
service vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its banner, the version of OpenSSL running on the remote
host is 1.1.0 prior to 1.1.0e. It is, therefore, affected by a denial
of service vulnerability that is triggered during a renegotiation
handshake in which the Encrypt-Then-Mac extension is negotiated when
it was not in the original handshake or vice-versa. An
unauthenticated, remote attacker can exploit this issue to cause
OpenSSL to crash, depending on which cipher suite is being used. Note
that both clients and servers are affected.");
  script_set_attribute(attribute:"see_also", value:"https://www.openssl.org/news/secadv/20170216.txt");
  script_set_attribute(attribute:"solution", value:
"Upgrade to OpenSSL version 1.1.0e or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-3733");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/02/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/02/23");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:openssl:openssl");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Web Servers");

  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("openssl_version.nasl");
  script_require_keys("openssl/port");

  exit(0);
}

include("openssl_version.inc");

openssl_check_version(fixed:'1.1.0e', min:"1.1.0", severity:SECURITY_WARNING);
  • NASL familyMisc.
    NASL idVIRTUALBOX_5_1_30.NASL
    descriptionThe version of Oracle VM VirtualBox running on the remote host is 5.1.x prior to 5.1.30. It is, therefore, affected by multiple vulnerabilities as noted in the October 2017 Critical Patch Update advisory. Please consult the CVRF details for the applicable CVEs for additional information. Nessus has not tested for these issues but has instead relied only on the application
    last seen2020-06-01
    modified2020-06-02
    plugin id103930
    published2017-10-18
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/103930
    titleOracle VM VirtualBox 5.1.x < 5.1.30 (October 2017 CPU)
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_1A802BA9F44411E69940B499BAEBFEAF.NASL
    descriptionThe OpenSSL project reports : Severity: High During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL to crash (dependent on ciphersuite). Both clients and servers are affected. This issue does not affect OpenSSL version 1.0.2.
    last seen2020-06-01
    modified2020-06-02
    plugin id97219
    published2017-02-17
    reporterThis script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/97219
    titleFreeBSD : openssl -- crash on handshake (1a802ba9-f444-11e6-9940-b499baebfeaf)

References