{"id":"CVE-2020-0601","kind":"vulnerability","aliases":["CVE-2020-0601"],"related":[],"title":"Microsoft Windows: Microsoft Windows CryptoAPI Spoofing Vulnerability","description":"Microsoft Windows CryptoAPI (Crypt32.dll) contains a spoofing vulnerability in the way it validates Elliptic Curve Cryptography (ECC) certificates. An attacker could exploit the vulnerability by using a spoofed code-signing certificate to sign a malicious executable, making it appear the file was from a trusted, legitimate source. A successful exploit could also allow the attacker to conduct man-in-the-middle attacks and decrypt confidential information on user connections to the affected software. The vulnerability is also known under the moniker of CurveBall.\n\nCISA required action: Apply updates per vendor instructions.","summary":"Windows CryptoAPI (Crypt32.dll) incorrectly validates ECC certificates, so a forged certificate passes as trusted. An attacker can sign malware so it looks like it came from a legitimate publisher, or intercept and decrypt connections that rely on the bad check.","severity":"high","cvss":8.1,"epss":0.89436,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"Microsoft Windows","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["code-signing","exploited","tls","vendor","windows","windows-server"],"not_affected_if":["patched-windows"],"how_to_check":null,"fix":"Apply the Microsoft security update for CVE-2020-0601 per vendor instructions (CISA KEV required action).","status":"open","published_at":"2020-01-14T23:15:30+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:39:51+00:00","updated_at":"2026-10-23T21:57:34+00:00","category":"vendor","confidence":0.8,"triage":{"at":"2026-10-23T21:39:51Z","model":"claude-haiku-5-5","output":{"fix":"Apply the Microsoft security update for CVE-2020-0601 per vendor instructions (CISA KEV required action).","reach":"network","impact":"high","summary":"Windows CryptoAPI (Crypt32.dll) incorrectly validates ECC certificates, so a forged certificate passes as trusted. An attacker can sign malware so it looks like it came from a legitimate publisher, or intercept and decrypt connections that rely on the bad check.","category":"vendor","who_cares":["windows","windows-server","code-signing","tls"],"confidence":0.8,"needs_auth":"no","worst_case":"Attacker runs malware disguised as trusted signed software or intercepts traffic.","analyst_note":"Confirm the patched Windows build numbers and a registry or PowerShell check from the Microsoft advisory for CVE-2020-0601; sources gave no check method.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["patched-windows"],"user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000484,"input_tokens":2973,"output_tokens":374,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Confirm the patched Windows build numbers and a registry or PowerShell check from the Microsoft advisory for CVE-2020-0601; sources gave no check method.","search":"'-0601':10A,13A '-2020':9A,12A 'action':153C 'affect':139C 'allow':119C 'also':118C,144C 'appear':105C 'appli':154C 'attack':41B,85C,121C,129C 'bad':64B 'came':50B 'certif':32B,36B,83C,97C 'check':65B 'cisa':151C 'code':17B,95C 'code-sign':16B,94C 'conduct':123C 'confidenti':132C 'connect':59B,136C 'contain':70C 'could':86C,117C 'crypt32.dll':28B,69C 'cryptoapi':5A,27B,68C 'cryptographi':81C 'curv':80C 'curvebal':150C 'cve':8A,11A 'decrypt':58B,131C 'ecc':31B,82C 'ellipt':79C 'execut':102C 'exploit':19B,87C,116C 'file':107C 'forg':35B 'incorrect':29B 'inform':133C 'instruct':158C 'intercept':56B 'known':145C 'legitim':53B,112C 'like':48B 'look':47B 'make':103C 'malici':101C 'malwar':44B 'man':125C 'man-in-the-middl':124C 'microsoft':1A,3A,14A,66C 'middl':128C 'monik':148C 'pass':37B 'per':156C 'publish':54B 'reli':61B 'requir':152C 'server':25B 'sign':18B,43B,96C,99C 'softwar':140C 'sourc':113C 'spoof':6A,72C,93C 'success':115C 'tls':20B 'trust':39B,111C 'updat':155C 'use':91C 'user':135C 'valid':30B,78C 'vendor':21B,157C 'vulner':7A,73C,89C,142C 'way':76C 'window':2A,4A,22B,24B,26B,67C 'windows':15A 'windows-serv':23B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2020-01-14T23:15:30+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2022-05-03","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2020-0601","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-0601","severity":null,"published_at":"2021-11-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:53+00:00","fetched_at":"2026-10-25T11:39:18+00:00","note":null},{"source":"epss","external_id":"CVE-2020-0601","url":"https://api.first.org/data/v1/epss?cve=CVE-2020-0601","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:44+00:00","fetched_at":"2026-10-23T19:13:44+00:00","note":null},{"source":"nvd","external_id":"CVE-2020-0601","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-0601","severity":null,"published_at":"2020-01-14T23:15:30+00:00","modified_at":"2026-06-17T02:46:08+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","fetched_at":"2026-10-23T21:57:34+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}