Vulnerabilities > CVE-2018-12019 - Improper Verification of Cryptographic Signature vulnerability in Enigmail
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
NONE Integrity impact
HIGH Availability impact
NONE 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
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 family Fedora Local Security Checks NASL id FEDORA_2018-A4BB79EA75.NASL description Security 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 seen 2020-06-05 modified 2019-01-03 plugin id 120669 published 2019-01-03 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/120669 title Fedora 28 : thunderbird-enigmail (2018-a4bb79ea75) NASL family SuSE Local Security Checks NASL id OPENSUSE-2019-477.NASL description This 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 seen 2020-05-31 modified 2019-03-27 plugin id 123195 published 2019-03-27 reporter This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/123195 title openSUSE Security Update : enigmail (openSUSE-2019-477) NASL family SuSE Local Security Checks NASL id OPENSUSE-2018-630.NASL description This 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 seen 2020-06-05 modified 2018-06-18 plugin id 110586 published 2018-06-18 reporter This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/110586 title openSUSE Security Update : enigmail (openSUSE-2018-630) NASL family Fedora Local Security Checks NASL id FEDORA_2018-FD67C19256.NASL description Security 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 seen 2020-06-05 modified 2018-06-25 plugin id 110674 published 2018-06-25 reporter This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/110674 title Fedora 27 : thunderbird-enigmail (2018-fd67c19256)
The Hacker News
id | THN:20BF2C23D315483B3CA9190D047C1212 |
last seen | 2019-04-30 |
modified | 2019-04-30 |
published | 2019-04-30 |
reporter | The Hacker News |
source | https://thehackernews.com/2019/04/email-signature-spoofing.html |
title | Over Dozen Popular Email Clients Found Vulnerable to Signature Spoofing Attacks |
References
- https://www.enigmail.net/index.php/en/download/changelog
- http://openwall.com/lists/oss-security/2018/06/13/10
- http://www.openwall.com/lists/oss-security/2019/04/30/4
- http://seclists.org/fulldisclosure/2019/Apr/38
- http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html
- https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.pdf
- https://github.com/RUB-NDS/Johnny-You-Are-Fired