Vulnerabilities > CVE-2018-12019 - Improper Verification of Cryptographic Signature vulnerability in Enigmail

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
CWE-347
nessus

Summary

The signature verification routine in Enigmail before 2.0.7 interprets user ids as status/control messages and does not correctly keep track of the status of multiple signatures, which allows remote attackers to spoof arbitrary email signatures via public keys containing crafted primary user ids.

Vulnerable Configurations

Part Description Count
Application
Enigmail
112

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 familyFedora Local Security Checks
    NASL idFEDORA_2018-A4BB79EA75.NASL
    descriptionSecurity fix CVE-2018-12019 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-05
    modified2019-01-03
    plugin id120669
    published2019-01-03
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/120669
    titleFedora 28 : thunderbird-enigmail (2018-a4bb79ea75)
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2019-477.NASL
    descriptionThis update for enigmail fixes vulnerabilities that allowed spoofing of e-mail signatures : - CVE-2018-12019: signature spoofing via specially crafted OpenPGP user IDs (boo#1097525) - CVE-2018-12020: signature spoofing via diagnostic output of the original file name in GnuPG verbose mode (boo#1096745) This mitigation prevents CVE-2018-12020 from being exploited even if GnuPG is not patched.
    last seen2020-05-31
    modified2019-03-27
    plugin id123195
    published2019-03-27
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/123195
    titleopenSUSE Security Update : enigmail (openSUSE-2019-477)
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2018-630.NASL
    descriptionThis update for enigmail fixes vulnerabilities that allowed spoofing of e-mail signatures : - CVE-2018-12019: signature spoofing via specially crafted OpenPGP user IDs (boo#1097525) - CVE-2018-12020: signature spoofing via diagnostic output of the original file name in GnuPG verbose mode (boo#1096745) This mitigation prevents CVE-2018-12020 from being exploited even if GnuPG is not patched.
    last seen2020-06-05
    modified2018-06-18
    plugin id110586
    published2018-06-18
    reporterThis script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/110586
    titleopenSUSE Security Update : enigmail (openSUSE-2018-630)
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2018-FD67C19256.NASL
    descriptionSecurity fix CVE-2018-12019 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-05
    modified2018-06-25
    plugin id110674
    published2018-06-25
    reporterThis script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/110674
    titleFedora 27 : thunderbird-enigmail (2018-fd67c19256)

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