Security readout for executives and security teams
Plain-English summary
CVE-2021-1359 lets a logged-in Cisco Web Security Appliance user with configuration-upload rights turn a configuration import into root-level command execution. The issue is serious for appliances with delegated administrators, but it is not a public unauthenticated takeover based on the provided sources.
Executive priority
Prioritize remediation for internet-reachable or broadly administered WSA management interfaces. The required authenticated access lowers urgency versus unauthenticated RCE, but successful exploitation gives root control of a security gateway.
Technical view
Cisco AsyncOS for Web Security Appliance insufficiently validates user-supplied XML in the web interface configuration management path. A remote authenticated attacker with permission to upload configuration files could submit crafted XML containing scripting code, execute operating-system commands, and elevate privileges to root.
Likely exposure
Exposure is limited to Cisco Web Security Appliance deployments running affected AsyncOS builds where users can access the web interface and upload configuration files. The source bundle does not name specific affected or fixed versions.
Exploitation context
The CVE is not listed as KEV in the provided data, and no cited source claims active exploitation. Exploitation requires a valid account with configuration-upload rights, network access to the web interface, and a vulnerable WSA device.
Researcher notes
Key constraints are PR:L, UI:N, AV:N, and root impact after successful command injection through XML configuration handling. Version and fix granularity are incomplete in the supplied bundle, so validation must rely on Cisco’s advisory.
Mitigation direction
- Review Cisco advisory for affected and fixed AsyncOS releases.
- Upgrade or patch WSA appliances according to Cisco guidance.
- Restrict WSA management access to trusted admin networks.
- Limit configuration-upload rights to tightly controlled administrators.
- Monitor appliance change logs for unexpected configuration imports.
Validation and detection
- Inventory Cisco Web Security Appliance deployments and AsyncOS versions.
- Compare installed versions against Cisco advisory guidance.
- Review user roles with configuration-upload permissions.
- Confirm web management is not broadly reachable.
- Check logs for suspicious configuration upload activity.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-112: Exact CWE lookup
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Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-1359 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L2.83.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- 20210707 Cisco Web Security Appliance Privilege Escalation VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing XML Validation
Missing XML Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.