Vulnerabilities > CVE-2017-17848 - Improper Verification of Cryptographic Signature vulnerability in multiple products

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
HIGH
Availability impact
NONE
network
low complexity
enigmail
debian
CWE-347
nessus
NVD
Published: 2017-12-27
Updated: 2019-05-16

Summary

An issue was discovered in Enigmail before 1.9.9. In a variant of CVE-2017-17847, signature spoofing is possible for multipart/related messages because a signed message part can be referenced with a cid: URI but not actually displayed. In other words, the entire containing message appears to be signed, but the recipient does not see any of the signed text.

Vulnerable Configurations

Part Description Count
Application
Enigmail
104
OS
Debian
3

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Padding Oracle Crypto Attack
    An attacker is able to efficiently decrypt data without knowing the decryption key if a target system leaks data on whether or not a padding error happened while decrypting the ciphertext. A target system that leaks this type of information becomes the padding oracle and an attacker is able to make use of that oracle to efficiently decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block). In addition to performing decryption, an attacker is also able to produce valid ciphertexts (i.e., perform encryption) by using the padding oracle, all without knowing the encryption key. Any cryptosystem can be vulnerable to padding oracle attacks if the encrypted messages are not authenticated to ensure their validity prior to decryption, and then the information about padding error is leaked to the attacker. This attack technique may be used, for instance, to break CAPTCHA systems or decrypt/modify state information stored in client side objects (e.g., hidden fields or cookies). This attack technique is a side-channel attack on the cryptosystem that uses a data leak from an improperly implemented decryption routine to completely subvert the cryptosystem. The one bit of information that tells the attacker whether a padding error during decryption has occurred, in whatever form it comes, is sufficient for the attacker to break the cryptosystem. That bit of information can come in a form of an explicit error message about a padding error, a returned blank page, or even the server taking longer to respond (a timing attack). This attack can be launched cross domain where an attacker is able to use cross-domain information leaks to get the bits of information from the padding oracle from a target system / service with which the victim is communicating. To do so an attacker sends a request containing ciphertext to the target system. Due to the browser's same origin policy, the attacker is not able to see the response directly, but can use cross-domain information leak techniques to still get the information needed (i.e., information on whether or not a padding error has occurred). For instance, this can be done using "img" tag plus the onerror()/onload() events. The attacker's JavaScript can make web browsers to load an image on the target site, and know if the image is loaded or not. This is 1-bit information needed for the padding oracle attack to work: if the image is loaded, then it is valid padding, otherwise it is not.

Nessus

  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DLA-1219.NASL
    descriptionMultiple vulnerabilities were discovered in Enigmail, an OpenPGP extension for Thunderbird, which could result in a loss of confidentiality, faked signatures, plain text leaks and denial of service. Additional information can be found under https://enigmail.net/download/other/Enigmail%20Pentest%20Report%20by%2 0Cure53%20-%20Excerpt.pdf For Debian 7
    last seen2020-03-17
    modified2017-12-26
    plugin id105426
    published2017-12-26
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/105426
    titleDebian DLA-1219-1 : enigmail security update
    code
    #%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory DLA-1219-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(105426);
  script_version("3.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12");

  script_cve_id("CVE-2017-17843", "CVE-2017-17844", "CVE-2017-17845", "CVE-2017-17846", "CVE-2017-17847", "CVE-2017-17848");

  script_name(english:"Debian DLA-1219-1 : enigmail 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 update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Multiple vulnerabilities were discovered in Enigmail, an OpenPGP
extension for Thunderbird, which could result in a loss of
confidentiality, faked signatures, plain text leaks and denial of
service. Additional information can be found under
https://enigmail.net/download/other/Enigmail%20Pentest%20Report%20by%2
0Cure53%20-%20Excerpt.pdf

For Debian 7 'Wheezy', these problems have been fixed in version
2:1.9.9-1~deb7u1.

We recommend that you upgrade your enigmail 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."
  );
  # https://enigmail.net/download/other/Enigmail%20Pentest%20Report%20by%20Cure53%20-%20Excerpt.pdf
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?6620e35f"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://lists.debian.org/debian-lts-announce/2017/12/msg00021.html"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/wheezy/enigmail"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Upgrade the affected enigmail package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/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:P/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:enigmail");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:7.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/12/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/26");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2020 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:"7.0", prefix:"enigmail", reference:"2:1.9.9-1~deb7u1")) 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_DSA-4070.NASL
    descriptionMultiple vulnerabilities were discovered in Enigmail, an OpenPGP extension for Thunderbird, which could result in a loss of confidentiality, faked signatures, plain text leaks and denial of service. Additional information can be found under https://enigmail.net/download/other/Enigmail%20Pentest%20Report%20by%2 0Cure53%20-%20Excerpt.pdf
    last seen2020-06-01
    modified2020-06-02
    plugin id105430
    published2017-12-26
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/105430
    titleDebian DSA-4070-1 : enigmail - security update
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-4070. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(105430);
  script_version("3.8");
  script_cvs_date("Date: 2019/05/07 12:34:16");

  script_cve_id("CVE-2017-17843", "CVE-2017-17844", "CVE-2017-17845", "CVE-2017-17846", "CVE-2017-17847", "CVE-2017-17848");
  script_xref(name:"DSA", value:"4070");

  script_name(english:"Debian DSA-4070-1 : enigmail - 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:
"Multiple vulnerabilities were discovered in Enigmail, an OpenPGP
extension for Thunderbird, which could result in a loss of
confidentiality, faked signatures, plain text leaks and denial of
service. Additional information can be found under
https://enigmail.net/download/other/Enigmail%20Pentest%20Report%20by%2
0Cure53%20-%20Excerpt.pdf"
  );
  # https://enigmail.net/download/other/Enigmail%20Pentest%20Report%20by%20Cure53%20-%20Excerpt.pdf
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?6620e35f"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/source-package/enigmail"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/jessie/enigmail"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/stretch/enigmail"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.debian.org/security/2017/dsa-4070"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the enigmail packages.

For the oldstable distribution (jessie), this problem has been fixed
in version 2:1.9.9-1~deb8u1.

For the stable distribution (stretch), this problem has been fixed in
version 2:1.9.9-1~deb9u1."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/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:P/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:enigmail");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:8.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/12/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/26");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2019 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:"enigmail", reference:"2:1.9.9-1~deb8u1")) flag++;
if (deb_check(release:"9.0", prefix:"enigmail", reference:"2:1.9.9-1~deb9u1")) 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");

The Hacker News

idTHN:20BF2C23D315483B3CA9190D047C1212
last seen2019-04-30
modified2019-04-30
published2019-04-30
reporterThe Hacker News
sourcehttps://thehackernews.com/2019/04/email-signature-spoofing.html
titleOver Dozen Popular Email Clients Found Vulnerable to Signature Spoofing Attacks

References