PuTTY < 0.81 Key Recovery Attack Vulnerability

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(193433);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/04/19");

  script_cve_id("CVE-2024-31497");
  script_xref(name:"IAVA", value:"2024-A-0243");

  script_name(english:"PuTTY < 0.81 Key Recovery Attack Vulnerability");

  script_set_attribute(attribute:"synopsis", value:
"The remote Windows host has an SSH client that is affected by an key recovery attack vulnerability.");
  script_set_attribute(attribute:"description", value:
"In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's 
NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a 
scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed 
messages may be publicly readable because they are stored in a public Git service that supports use of SSH 
for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other 
words, an adversary may already have enough signature information to compromise a victim's private key, even 
if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to 
conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the 
adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), 
even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH 
connections to other services operated by other entities. Here, the rogue server operator (who would 
otherwise have no way to determine the victim's private key) can derive the victim's private key, and then 
use it for unauthorized access to those other services. If the other services include Git services, then 
again it may be possible to conduct supply-chain attacks on software maintained in Git. 

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported 
version number.");
  # https://thehackernews.com/2024/04/widely-used-putty-ssh-client-found.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?0d963cbf");
  script_set_attribute(attribute:"solution", value:
"Upgrade to PuTTY version 0.81 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N");
  script_set_attribute(attribute:"cvss_score_source", value:"manual");
  script_set_attribute(attribute:"cvss_score_rationale", value:"Score from an in depth analysis done by Tenable");

  script_set_attribute(attribute:"vuln_publication_date", value:"2024/04/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2024/04/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2024/04/17");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:simon_tatham:putty");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Windows");

  script_copyright(english:"This script is Copyright (C) 2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("putty_installed.nasl");
  script_require_keys("installed_sw/PuTTY", "SMB/Registry/Enumerated");

  exit(0);
}

include('vcf.inc');

get_kb_item_or_exit("SMB/Registry/Enumerated");

var app_info = vcf::get_app_info(app:"PuTTY", win_local:TRUE);

var constraints = [
   { "min_version" : "0.68", "fixed_version" : "0.81" }
];

vcf::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_WARNING);