A message-forgery issue was discovered in crypto/openpgp/clearsign/clearsign.go in supplementary Go cryptography libraries 2019-03-25. According to the OpenPGP Message Format specification in RFC 4880 chapter 7, a cleartext signed message can contain one or more optional "Hash" Armor Headers. The "Hash" Armor Header specifies the message digest algorithm(s) used for the signature. However, the Go clearsign package ignores the value of this header, which allows an attacker to spoof it. Consequently, an attacker can lead a victim to believe the signature was generated using a different message digest algorithm than what was actually used. Moreover, since the library skips Armor Header parsing in general, an attacker can not only embed arbitrary Armor Headers, but also prepend arbitrary text to cleartext messages without invalidating the signatures.

The remote Debian 10 host has a package installed that is affected by multiple vulnerabilities as referenced in the dla-3455 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-3455-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                      Markus Koschany     June 16, 2023                                 https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : golang-go.crypto     Version        : 1:0.0~git20181203.505ab14-1+deb10u1     CVE ID         : CVE-2019-11840 CVE-2019-11841 CVE-2020-9283     Debian Bug     : 952462

    Several security vulnerabilities have been discovered in golang-go.crypto, the     supplementary Go cryptography libraries.

    CVE-2019-11840

        An issue was discovered in supplementary Go cryptography libraries, aka         golang-googlecode-go-crypto. If more than 256 GiB of keystream is         generated, or if the counter otherwise grows greater than 32 bits, the         amd64 implementation will first generate incorrect output, and then cycle         back to previously generated keystream. Repeated keystream bytes can lead         to loss of confidentiality in encryption applications, or to predictability         in CSPRNG applications.

    CVE-2019-11841

        A message-forgery issue was discovered in         crypto/openpgp/clearsign/clearsign.go in supplementary Go cryptography         libraries. The Hash Armor Header specifies the message digest         algorithm(s) used for the signature. Since the library skips Armor Header         parsing in general, an attacker can not only embed arbitrary Armor Headers,         but also prepend arbitrary text to cleartext messages without invalidating         the signatures.

    CVE-2020-9283

        golang.org/x/crypto allows a panic during signature verification in the         golang.org/x/crypto/ssh package. A client can attack an SSH server that         accepts public keys. Also, a server can attack any SSH client.

    The following Go packages have been rebuilt in order to fix the aforementioned     issues.

    rclone: 1.45-3+deb10u1     obfs4proxy: 0.0.7-4+deb10u1     gobuster: 2.0.1-1+deb10u1     restic: 0.9.4+ds-2+deb10u1     gopass: 1.2.0-2+deb10u1     aptly: 1.3.0+ds1-2.2~deb10u2:
    dnscrypt-proxy: 2.0.19+ds1-2+deb10u1     g10k: 0.5.7-1+deb10u1     hub: 2.7.0~ds1-1+deb10u1     acmetool: 0.0.62-3+deb10u1     syncthing: 1.0.0~ds1-1+deb10u1     packer: 1.3.4+dfsg-4+deb10u1     etcd: 3.2.26+dfsg-3+deb10u1     notary: 0.6.1~ds1-3+deb10u1

    For Debian 10 buster, these problems have been fixed in version     1:0.0~git20181203.505ab14-1+deb10u1.

    We recommend that you upgrade your golang-go.crypto packages.

    For the detailed security status of golang-go.crypto please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/golang-go.crypto

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS     Attachment:
    signature.asc     Description: This is a digitally signed message part

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

CVE-2019-11840

An issue was discovered in supplementary Go cryptography libraries, aka golang-googlecode-go-crypto. If more than 256 GiB of keystream is generated, or if the counter otherwise grows greater than 32 bits, the amd64 implementation will first generate incorrect output, and then cycle back to previously generated keystream. Repeated keystream bytes can lead to loss of confidentiality in encryption applications, or to predictability in CSPRNG applications.

CVE-2019-11841

A message-forgery issue was discovered in crypto/openpgp/clearsign/clearsign.go in supplementary Go cryptography libraries. The 'Hash' Armor Header specifies the message digest algorithm(s) used for the signature. Since the library skips Armor Header parsing in general, an attacker can not only embed arbitrary Armor Headers, but also prepend arbitrary text to cleartext messages without invalidating the signatures.

CVE-2020-9283

golang.org/x/crypto allows a panic during signature verification in the golang.org/x/crypto/ssh package. A client can attack an SSH server that accepts public keys. Also, a server can attack any SSH client.

For Debian 9 stretch, these problems have been fixed in version 1:0.0~git20170407.0.55a552f+REALLY.0.0~git20161012.0.5f31782-1+deb8u1.

We recommend that you upgrade your golang-go.crypto packages.

For the detailed security status of golang-go.crypto please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/golang-go.crypto

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.

This package ignored the value of the Hash header, which allows an attacker to spoof it. An attacker can not only embed arbitrary Armor Headers, but also prepend arbitrary text to cleartext messages without invalidating the signatures.

For Debian 8 'Jessie', this problem has been fixed in version 0.0~hg190-1+deb8u2.

We recommend that you upgrade your golang-go.crypto 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.

ID	Name	Product	Family	Severity
177400	Debian dla-3455 : golang-golang-x-crypto-dev - security update	Nessus	Debian Local Security Checks	medium
141271	Debian DLA-2402-1 : golang-go.crypto security update	Nessus	Debian Local Security Checks	medium
128780	Debian DLA-1920-1 : golang-go.crypto security update	Nessus	Debian Local Security Checks	medium

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