{"schemaVersion":3,"id":"CVE-2021-27877","aliases":[],"status":"published","duplicateOf":null,"title":"Veritas Backup Exec Agent Improper Authentication Vulnerability","description":"An issue was discovered in Veritas Backup Exec before 21.2. It supports multiple authentication schemes: SHA authentication is one of these. This authentication scheme is no longer used in current versions of the product, but hadn't yet been disabled. An attacker could remotely exploit this scheme to gain unauthorized access to an Agent and execute privileged commands.","dates":{"published":"2021-03-01T21:49:36.000Z","modified":"2025-10-21T23:25:53.349Z","reserved":null,"kevAdded":["2023-04-07T00:00:00.000Z"],"kevDue":["2023-04-28T00:00:00.000Z"]},"cvss":{"headline":{"score":9.8,"severity":"critical","version":"3.1","versionLabel":"v3.1","source":"NVD","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":8.2,"severity":"high","vector":"CVSS:3.1/AC:L/AV:N/A:N/C:H/I:L/PR:N/S:U/UI:N","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":9.8,"severity":"critical","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":7.5,"severity":"high","vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.6491,"percentile":0.99244,"severity":"critical","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-19T00:00:00.000Z","baselineScore":0.6491},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.6491,"percentile":0.99244}],"last30":[{"date":"2026-09-19T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.6491,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.6491,"percentile":0.99244}]},"kev":{"state":"listed","entries":[{"source":"cisa","sourceLabel":"CISA","dateAdded":"2023-04-07T00:00:00.000Z","dueDate":"2023-04-28T00:00:00.000Z","requiredAction":"Apply updates per vendor instructions.","name":"Veritas Backup Exec Agent Improper Authentication Vulnerability","description":"Veritas Backup Exec (BE) Agent contains an improper authentication vulnerability that could allow an attacker unauthorized access to the BE Agent via SHA authentication scheme.","notes":[{"type":"url","href":"https://www.veritas.com/support/en_US/security/VTS21-001","label":"www.veritas.com/support/en_US/security/VTS21-001"},{"type":"url","href":"https://nvd.nist.gov/vuln/detail/CVE-2021-27877","label":"nvd.nist.gov/vuln/detail/CVE-2021-27877"}],"vendor":"Veritas","product":"Backup Exec Agent","ransomware":true,"ransomwareUse":"Known","exploitationType":null}],"listedCount":1,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":true,"entry":{"source":"cisa","sourceLabel":"CISA","dateAdded":"2023-04-07T00:00:00.000Z","dueDate":"2023-04-28T00:00:00.000Z","requiredAction":"Apply updates per vendor instructions.","name":"Veritas Backup Exec Agent Improper Authentication Vulnerability","description":"Veritas Backup Exec (BE) Agent contains an improper authentication vulnerability that could allow an attacker unauthorized access to the BE Agent via SHA authentication scheme.","notes":[{"type":"url","href":"https://www.veritas.com/support/en_US/security/VTS21-001","label":"www.veritas.com/support/en_US/security/VTS21-001"},{"type":"url","href":"https://nvd.nist.gov/vuln/detail/CVE-2021-27877","label":"nvd.nist.gov/vuln/detail/CVE-2021-27877"}],"vendor":"Veritas","product":"Backup Exec Agent","ransomware":true,"ransomwareUse":"Known","exploitationType":null}},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"known","sources":["cisa"]},"exploits":[{"id":"REF_D8B739D305EFA1DE","name":"Exploit Reference (packetstormsecurity.com)","source":"reference","url":"http://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html","maturity":"unknown","reliabilityScore":0.2,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null},{"id":"MSF_EXPLOIT_MULTI_VERITAS_BEAGENT_SHA_AUTH_RCE","name":"Veritas Backup Exec Agent Remote Code Execution","source":"metasploit","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploit/multi/veritas/beagent_sha_auth_rce.rb","maturity":"weaponized","reliabilityScore":1,"verified":true,"type":"remote","platforms":[],"requiresAuth":false,"exploitdb":null,"metasploit":{"fullname":"exploit/multi/veritas/beagent_sha_auth_rce","rank":"600","rankName":"excellent","postAuth":false,"check":true,"stability":["crash-safe"],"sideEffects":["artifacts-on-disk","ioc-in-logs"],"reliability":["unreliable-session"]}}],"exploitCount":2,"weaknesses":[],"affected":[{"vendor":"veritas","product":"backup_exec","name":"backup exec","label":"backup_exec","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 21.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 21.2","eol":null,"hubHref":"/vendor/veritas/backup_exec"}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://www.veritas.com/content/support/en_US/security/VTS21-001#issue1","label":"www.veritas.com/content/support/en_US/security/VTS21-001","hostname":"www.veritas.com","tags":["X Refsource MISC","Vendor Advisory"]},{"url":"http://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html","label":"packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html","hostname":"packetstormsecurity.com","tags":["X Refsource MISC","Exploit","Third Party Advisory","VDB Entry"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27877","label":"www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27877","hostname":"www.cisa.gov","tags":["Government Resource","US Government Resource"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2021-03-01T21:49:36.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"kev-added","date":"2023-04-07T00:00:00.000Z","label":"Added to CISA KEV","detail":"Veritas Backup Exec Agent Improper Authentication Vulnerability","source":"cisa"},{"kind":"kev-due","date":"2023-04-28T00:00:00.000Z","label":"CISA remediation due","detail":"Apply updates per vendor instructions.","source":"cisa"},{"kind":"modified","date":"2025-10-21T23:25:53.349Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":90,"level":"critical","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-19T18:18:19.466Z","stale":false,"partial":false}}