Vulnerabilities > CVE-2018-20743 - 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
mumble
debian
CWE-20
nessus

Summary

murmur in Mumble through 1.2.19 before 2018-08-31 mishandles multiple concurrent requests that are persisted in the database, which allows remote attackers to cause a denial of service (daemon hang or crash) via a message flood.

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 familyDebian Local Security Checks
    NASL idDEBIAN_DSA-4402.NASL
    descriptionIt was discovered that insufficient restrictions in the connection handling of Mumble, a low latency encrypted VoIP client, could result in denial of service.
    last seen2020-06-01
    modified2020-06-02
    plugin id122621
    published2019-03-06
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/122621
    titleDebian DSA-4402-1 : mumble - security update
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Debian Security Advisory DSA-4402. The text 
    # itself is copyright (C) Software in the Public Interest, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(122621);
      script_version("1.2");
      script_cvs_date("Date: 2020/02/06");
    
      script_cve_id("CVE-2018-20743");
      script_xref(name:"DSA", value:"4402");
    
      script_name(english:"Debian DSA-4402-1 : mumble - security update");
      script_summary(english:"Checks dpkg output for the updated package");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote Debian host is missing a security-related update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "It was discovered that insufficient restrictions in the connection
    handling of Mumble, a low latency encrypted VoIP client, could result
    in denial of service."
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security-tracker.debian.org/tracker/source-package/mumble"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://packages.debian.org/source/stretch/mumble"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://www.debian.org/security/2019/dsa-4402"
      );
      script_set_attribute(
        attribute:"solution", 
        value:
    "Upgrade the mumble packages.
    
    For the stable distribution (stretch), this problem has been fixed in
    version 1.2.18-1+deb9u1."
      );
      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:"exploitability_ease", value:"No known exploits are available");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:mumble");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2019/01/25");
      script_set_attribute(attribute:"patch_publication_date", value:"2019/03/05");
      script_set_attribute(attribute:"plugin_publication_date", value:"2019/03/06");
      script_set_attribute(attribute:"generated_plugin", value:"current");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"Debian Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/Debian/release", "Host/Debian/dpkg-l");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("debian_package.inc");
    
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    if (!get_kb_item("Host/Debian/release")) audit(AUDIT_OS_NOT, "Debian");
    if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    
    flag = 0;
    if (deb_check(release:"9.0", prefix:"mumble", reference:"1.2.18-1+deb9u1")) flag++;
    if (deb_check(release:"9.0", prefix:"mumble-dbg", reference:"1.2.18-1+deb9u1")) flag++;
    if (deb_check(release:"9.0", prefix:"mumble-server", reference:"1.2.18-1+deb9u1")) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_warning(port:0, extra:deb_report_get());
      else security_warning(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");
    
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2019-1794.NASL
    descriptionThis update for mumble fixes the following issues : CVE-2018-20743: murmur mishandled multiple concurrent requests that were persisted in the database, which allowed remote attackers to cause a denial of service (daemon hang or crash) via a message flood. (boo#1123334)
    last seen2020-06-01
    modified2020-06-02
    plugin id126978
    published2019-07-24
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126978
    titleopenSUSE Security Update : mumble (openSUSE-2019-1794)
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DLA-1661.NASL
    descriptionIt has been found that the mumble-server mishandles multiple concurrent requests that are persisted in the database, which allows remote attackers to cause a denial of service (daemon hang or crash) via a message flood. With the new security update a rate limiter is added with Leaky-Bucket algorithm. For Debian 8
    last seen2020-03-17
    modified2019-02-07
    plugin id121624
    published2019-02-07
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/121624
    titleDebian DLA-1661-1 : mumble security update