Allele Security Alert
ASA-2019-00528
Identifier(s)
ASA-2019-00528, CVE-2019-9153
Title
Message Signature Bypass
Vendor(s)
ProtonMail
Product(s)
OpenPGP.js
Affected version(s)
OpenPGP.js versions before 4.2.0
Fixed version(s)
OpenPGP.js version 4.2.0
Proof of concept
Yes
Description
During verification of a message signature, OpenPGP.js does not verify that the signature is of type text. An attacker could therefore construct a message that, instead of a text signature, contains a signature of another type. As the input required for the verification process depends on the signature type, an attacker could use a signature with a type that only verifies its subpackets and does not require additional input.
An attacker could construct a message that contains a valid “standalone” or “timestamp” signature packet signed by another person. OpenPGP.js would incorrectly assume this message to be signed by that person.
Technical details
Unknown
Credits
Wolfgang Ettlinger (SEC Consult Vulnerability Lab)
Reference(s)
Multiple Vulnerabilities in OpenPGP.js
https://sec-consult.com/en/blog/advisories/multiple-vulnerabilities-in-openpgp-js/
Mailvelope Extensions Security Audit
https://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/Publications/Studies/Mailvelope_Extensions/Mailvelope_Extensions_pdf.html
Mailvelope Extensions Security Audit [PDF]
https://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/Publications/Studies/Mailvelope_Extensions/Mailvelope_Extensions_pdf.pdf?__blob=publicationFile
SEC_Consult_BSI_Mailvelope-message_signature_bypass.txt
https://sec-consult.com/wp-content/uploads/2019/08/SEC_Consult_BSI_Mailvelope-message_signature_bypass.txt
Release v4.2.0 – Security Release · openpgpjs/openpgpjs
https://github.com/openpgpjs/openpgpjs/releases/tag/v4.2.0
Only accept binary or text signatures when verifying messages
https://github.com/openpgpjs/openpgpjs/pull/797/commits/327d3e5392a6f59a4270569d200c7f7a2bfc4cbc
CVE-2019-9153
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-9153
CVE-2019-9153
https://nvd.nist.gov/vuln/detail/CVE-2019-9153
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Last modified: September 4, 2019