Vulnerabilities > CVE-2018-16948 - Information Exposure vulnerability in multiple products

047910
CVSS 5.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
NONE
Availability impact
NONE
network
low complexity
openafs
debian
CWE-200
nessus
NVD
Published: 2018-09-12
Updated: 2018-11-19

Summary

An issue was discovered in OpenAFS before 1.6.23 and 1.8.x before 1.8.2. Several RPC server routines did not fully initialize their output variables before returning, leaking memory contents from both the stack and the heap. Because the OpenAFS cache manager functions as an Rx server for the AFSCB service, clients are also susceptible to information leakage. For example, RXAFSCB_TellMeAboutYourself leaks kernel memory and KAM_ListEntry leaks kaserver memory.

Vulnerable Configurations

Part Description Count
Application
Openafs
194
OS
Debian
2

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Subverting Environment Variable Values
    The attacker directly or indirectly modifies environment variables used by or controlling the target software. The attacker's goal is to cause the target software to deviate from its expected operation in a manner that benefits the attacker.
  • Footprinting
    An attacker engages in probing and exploration activity to identify constituents and properties of the target. Footprinting is a general term to describe a variety of information gathering techniques, often used by attackers in preparation for some attack. It consists of using tools to learn as much as possible about the composition, configuration, and security mechanisms of the targeted application, system or network. Information that might be collected during a footprinting effort could include open ports, applications and their versions, network topology, and similar information. While footprinting is not intended to be damaging (although certain activities, such as network scans, can sometimes cause disruptions to vulnerable applications inadvertently) it may often pave the way for more damaging attacks.
  • Exploiting Trust in Client (aka Make the Client Invisible)
    An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
  • Browser Fingerprinting
    An attacker carefully crafts small snippets of Java Script to efficiently detect the type of browser the potential victim is using. Many web-based attacks need prior knowledge of the web browser including the version of browser to ensure successful exploitation of a vulnerability. Having this knowledge allows an attacker to target the victim with attacks that specifically exploit known or zero day weaknesses in the type and version of the browser used by the victim. Automating this process via Java Script as a part of the same delivery system used to exploit the browser is considered more efficient as the attacker can supply a browser fingerprinting method and integrate it with exploit code, all contained in Java Script and in response to the same web page request by the browser.
  • Session Credential Falsification through Prediction
    This attack targets predictable session ID in order to gain privileges. The attacker can predict the session ID used during a transaction to perform spoofing and session hijacking.

Nessus

  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DSA-4302.NASL
    descriptionSeveral vulnerabilities were discovered in openafs, an implementation of the distributed filesystem AFS. The Common Vulnerabilities and Exposures project identifies the following problems : - CVE-2018-16947 Jeffrey Altman reported that the backup tape controller (butc) process does accept incoming RPCs but does not require (or allow for) authentication of those RPCs, allowing an unauthenticated attacker to perform volume operations with administrator credentials. - CVE-2018-16948 Mark Vitale reported that several RPC server routines do not fully initialize output variables, leaking memory contents (from both the stack and the heap) to the remote caller for otherwise-successful RPCs. - CVE-2018-16949 Mark Vitale reported that an unauthenticated attacker can consume large amounts of server memory and network bandwidth via specially crafted requests, resulting in denial of service to legitimate clients.
    last seen2020-06-01
    modified2020-06-02
    plugin id117675
    published2018-09-25
    reporterThis script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/117675
    titleDebian DSA-4302-1 : openafs - security update
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-4302. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(117675);
  script_version("1.4");
  script_cvs_date("Date: 2018/11/20 11:04:16");

  script_cve_id("CVE-2018-16947", "CVE-2018-16948", "CVE-2018-16949");
  script_xref(name:"DSA", value:"4302");

  script_name(english:"Debian DSA-4302-1 : openafs - 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:
"Several vulnerabilities were discovered in openafs, an implementation
of the distributed filesystem AFS. The Common Vulnerabilities and
Exposures project identifies the following problems :

  - CVE-2018-16947
    Jeffrey Altman reported that the backup tape controller
    (butc) process does accept incoming RPCs but does not
    require (or allow for) authentication of those RPCs,
    allowing an unauthenticated attacker to perform volume
    operations with administrator credentials.

  - CVE-2018-16948
    Mark Vitale reported that several RPC server routines do
    not fully initialize output variables, leaking memory
    contents (from both the stack and the heap) to the
    remote caller for otherwise-successful RPCs.

  - CVE-2018-16949
    Mark Vitale reported that an unauthenticated attacker
    can consume large amounts of server memory and network
    bandwidth via specially crafted requests, resulting in
    denial of service to legitimate clients."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=908616"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2018-16947"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2018-16948"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/CVE-2018-16949"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/source-package/openafs"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/stretch/openafs"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.debian.org/security/2018/dsa-4302"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the openafs packages.

For the stable distribution (stretch), these problems have been fixed
in version 1.6.20-2+deb9u2."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2018/09/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/09/25");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018 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:"libafsauthent1", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"libafsrpc1", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"libkopenafs1", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"libopenafs-dev", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"libpam-openafs-kaserver", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-client", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-dbserver", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-doc", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-fileserver", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-fuse", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-kpasswd", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-krb5", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-modules-dkms", reference:"1.6.20-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"openafs-modules-source", reference:"1.6.20-2+deb9u2")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_hole(port:0, extra:deb_report_get());
  else security_hole(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DLA-1513.NASL
    descriptionSeveral security vulnerabilities were discovered in OpenAFS, a distributed file system. CVE-2018-16947 The backup tape controller process accepts incoming RPCs but does not require (or allow for) authentication of those RPCs. Handling those RPCs results in operations being performed with administrator credentials, including dumping/restoring volume contents and manipulating the backup database. CVE-2018-16948 Several RPC server routines did not fully initialize their output variables before returning, leaking memory contents from both the stack and the heap. Because the OpenAFS cache manager functions as an Rx server for the AFSCB service, clients are also susceptible to information leakage. CVE-2018-16949 Several data types used as RPC input variables were implemented as unbounded array types, limited only by the inherent 32-bit length field to 4GB. An unauthenticated attacker could send, or claim to send, large input values and consume server resources waiting for those inputs, denying service to other valid connections. For Debian 8
    last seen2020-06-01
    modified2020-06-02
    plugin id117640
    published2018-09-24
    reporterThis script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/117640
    titleDebian DLA-1513-1 : openafs security update
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory DLA-1513-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(117640);
  script_version("1.2");
  script_cvs_date("Date: 2018/11/20 11:04:16");

  script_cve_id("CVE-2018-16947", "CVE-2018-16948", "CVE-2018-16949");

  script_name(english:"Debian DLA-1513-1 : openafs security update");
  script_summary(english:"Checks dpkg output for the updated packages.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Debian host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Several security vulnerabilities were discovered in OpenAFS, a
distributed file system.

CVE-2018-16947

The backup tape controller process accepts incoming RPCs but does not
require (or allow for) authentication of those RPCs. Handling those
RPCs results in operations being performed with administrator
credentials, including dumping/restoring volume contents and
manipulating the backup database.

CVE-2018-16948

Several RPC server routines did not fully initialize their output
variables before returning, leaking memory contents from both the
stack and the heap. Because the OpenAFS cache manager functions as an
Rx server for the AFSCB service, clients are also susceptible to
information leakage.

CVE-2018-16949

Several data types used as RPC input variables were implemented as
unbounded array types, limited only by the inherent 32-bit length
field to 4GB. An unauthenticated attacker could send, or claim to
send, large input values and consume server resources waiting for
those inputs, denying service to other valid connections.

For Debian 8 'Jessie', these problems have been fixed in version
1.6.9-2+deb8u8.

We recommend that you upgrade your openafs packages.

NOTE: Tenable Network Security has extracted the preceding description
block directly from the DLA security advisory. Tenable has attempted
to automatically clean and format it as much as possible without
introducing additional issues."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://lists.debian.org/debian-lts-announce/2018/09/msg00024.html"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/jessie/openafs"
  );
  script_set_attribute(attribute:"solution", value:"Upgrade the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libafsauthent1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libafsrpc1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libkopenafs1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libopenafs-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libpam-openafs-kaserver");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-client");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-dbg");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-dbserver");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-fileserver");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-fuse");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-kpasswd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-krb5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-modules-dkms");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:openafs-modules-source");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:8.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2018/09/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/09/24");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018 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:"8.0", prefix:"libafsauthent1", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"libafsrpc1", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"libkopenafs1", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"libopenafs-dev", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"libpam-openafs-kaserver", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-client", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-dbg", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-dbserver", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-doc", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-fileserver", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-fuse", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-kpasswd", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-krb5", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-modules-dkms", reference:"1.6.9-2+deb8u8")) flag++;
if (deb_check(release:"8.0", prefix:"openafs-modules-source", reference:"1.6.9-2+deb8u8")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_hole(port:0, extra:deb_report_get());
  else security_hole(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");

References