CVE intelligence and bounded remediation
CVE-2021-1145 — Cisco Staros security vulnerability
A vulnerability in the Secure FTP (SFTP) of Cisco StarOS for Cisco ASR 5000 Series Routers could allow an authenticated, remote attacker to read arbitrary files on an affected device. To exploit this vulnerability, the attacker would need to have valid credentials on the affected device. The vulnerability is due to insecure handling of symbolic links. An attacker could exploit this vulnerability by sending a crafted SFTP command to an affected device. A successful exploit could allow the attacker to read arbitrary files on the affected device.
- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Published
- 2021-01-13
- CISA KEV
- Not currently listed
- Ecosystem
- operating-system
- Weaknesses
- CWE-61, CWE-59
Affected products
- cisco / staros
Matched remediation archetype
Path traversal, unsafe upload, and file handling
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
- Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
- Review canonicalization and containment checks across supported operating systems and storage backends.
Remediate safely
- Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
- Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
- Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.
Authoritative sources
Complete CVE record and remediation plan
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