{"schemaVersion":3,"id":"CVE-2021-27876","aliases":[],"status":"published","duplicateOf":null,"title":"Veritas Backup Exec Agent File Access Vulnerability","description":"An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client and an Agent requires successful authentication, which is typically completed over a secure TLS communication. However, due to a vulnerability in the SHA Authentication scheme, an attacker is able to gain unauthorized access and complete the authentication process. Subsequently, the client can execute data management protocol commands on the authenticated connection. By using crafted input parameters in one of these commands, an attacker can access an arbitrary file on the system using System privileges.","dates":{"published":"2021-03-01T21:49:06.000Z","modified":"2025-10-21T23:25:53.626Z","reserved":null,"kevAdded":["2023-04-07T00:00:00.000Z"],"kevDue":["2023-04-28T00:00:00.000Z"]},"cvss":{"headline":{"score":8.1,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AC:L/AV:N/A:N/C:H/I:H/PR:L/S:U/UI:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":8.1,"severity":"high","vector":"CVSS:3.1/AC:L/AV:N/A:N/C:H/I:H/PR:L/S:U/UI:N","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":8.1,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","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:S/C:C/I:P/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.13518,"percentile":0.96418,"severity":"medium","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-19T00:00:00.000Z","baselineScore":0.13518},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.13518,"percentile":0.96418}],"last30":[{"date":"2026-09-19T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.13518,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.13518,"percentile":0.96418}]},"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 File Access Vulnerability","description":"Veritas Backup Exec (BE) Agent contains a file access vulnerability that could allow an attacker to specially craft input parameters on a data management protocol command to access files on the BE Agent machine.","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-2021-27876","label":"nvd.nist.gov/vuln/detail/CVE-2021-27876"}],"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 File Access Vulnerability","description":"Veritas Backup Exec (BE) Agent contains a file access vulnerability that could allow an attacker to specially craft input parameters on a data management protocol command to access files on the BE Agent machine.","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-2021-27876","label":"nvd.nist.gov/vuln/detail/CVE-2021-27876"}],"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#issue2","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-2021-27876","label":"www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27876","hostname":"www.cisa.gov","tags":["Government Resource","US Government Resource"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2021-03-01T21:49:06.000Z","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 File Access 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":"2025-10-21T23:25:53.626Z","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":"2026-10-19T16:43:00.194Z","stale":false,"partial":false}}