Attackers use Archive File to bundle, compress, and sometimes conceal malicious content for delivery, staging, or exfiltration. Archives can hide scripts, executables, or data inside nested structures, so defenders should inspect archive contents, watch for password-protected or unusually deep archives, and apply content controls at ingress and egress.
How attackers use archive files
archive file help attackers package malicious content so it is easier to move, hide, and deliver. The archive may be the payload itself, or it may act as a container that delays inspection until a user opens it, extracts it, or trusts its contents. That makes archives useful for staging, delivery, and exfiltration.
Attackers often rely on the fact that archives look routine. A compressed file can disguise a script, installer, shortcut, or document chain inside nested folders and multiple layers of compression. That structure can also frustrate simple filtering if defenders only check filenames or outer file type instead of the full archive tree.
Archive abuse becomes more effective when the file format supports encryption, nesting, or metadata quirks. Password-protected archives can block content inspection, while unusually deep or recursive archives can create operational friction for scanners, sandboxes, and email gateways. The core security issue is not compression itself, but the gap between what the outer file looks like and what it actually contains.
Why archives are useful for delivery, staging, and exfiltration
For delivery, archives let an attacker bundle several components together, which may include a loader, a decoy document, and embedded instructions. That packaging can improve success rates because the victim receives one file that appears legitimate. For staging, archives can carry tools and data into an environment in a form that is compact and easy to unpack when the attacker reaches a foothold.
For exfiltration, archives are attractive because they compress data before transmission and can hide what is being moved until it is opened elsewhere. This can reduce transfer size, make a large set of files appear as a single attachment, and complicate content inspection at egress. The same technique that supports normal backup and transfer workflows can therefore be reused for malicious collection and removal of data.
Defenders should focus on the full archive path, not just the file extension. The meaningful questions are what was packaged, who sent it, whether the archive structure is unusual, and whether extraction would reveal executable or script content that should not have crossed the boundary.
What to inspect when archive abuse is suspected
Inspection should go beyond the archive header and into nested members, embedded executables, scripts, and shortcut files. Password protection, repeated nesting, unusual compression ratios, and mismatches between the outer name and inner content are all practical warning signs. Content controls at ingress and egress matter because they address both inbound delivery and outbound data movement.
Modern inspection usually benefits from two layers of control: policy enforcement and content analysis. Policy can restrict risky archive types, set recursion limits, or quarantine encrypted attachments for review. Content analysis can unpack the archive, compare file types to expected usage, and flag archive members that are executable, auto-starting, or otherwise inconsistent with the business context.
Useful detection also includes behaviour after extraction. If an archive arrives from an untrusted source and then spawns unusual scripts, drops new executables, or initiates outbound connections, the archive was likely a delivery vehicle rather than an innocent attachment.
Risk and Threat Considerations
Archives are a durable abuse path because they combine concealment with normal business utility. The same features that make them practical for software distribution and document exchange also let attackers smuggle payloads past weak filtering or delay detection until extraction.
Failure mechanism: Defenders inspect only the outer container, allow encrypted or deeply nested archives through policy, or fail to validate the inner file types and extraction behaviour. That leaves malicious content hidden until a user opens it or a downstream system processes it.
Impact: The archive can enable initial compromise, payload staging, or data exfiltration while reducing the chance that simple gateway controls will notice the real content. In mature environments, the concern is less about the archive itself and more about the trust boundary it creates between receipt, extraction, and execution.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
MITRE ATT&CK and OWASP Non-Human Identity Top 10 address the attack and risk surface, while CIS Controls v8 and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| MITRE ATT&CK | T1027 — Obfuscated Files or Information | Archive nesting and concealment map to attacker payload hiding and evasion. |
| T1560 — Archive Collected Data | The question asks how archives are used for staging and exfiltration. | |
| Recommendation — Inspect nested archives and flag encrypted or unusually deep containers that hide payloads. Hunt for archive creation on systems that are collecting data for exfiltration. | ||
| CIS Controls v8 | CIS-10 — Malware Defenses | Archive inspection and content controls are core malware-delivery defenses. |
| Recommendation — Scan archive contents recursively and quarantine suspicious attachments before extraction. | ||
| NIST SP 800-53 Rev 5 | SI-3 — Malicious Code Protection | Archives can deliver malware and require content inspection at ingress and egress. |
| Recommendation — Apply malicious code scanning to archive members, not just the outer file. | ||
| OWASP Non-Human Identity Top 10 | NHI-02 — Secret Leakage | Archives may conceal exported secrets or credentials during exfiltration. |
| Recommendation — Detect and block archives that package secrets, keys, or tokens for outbound transfer. | ||
Practitioner Guidance
What to verify: Confirm that mail, web, and file-transfer controls inspect the archive recursively, not just at the top level. If encrypted archives are allowed, make sure there is an explicit business justification and a review path for what arrives protected from inspection.
What to prioritise: Treat password-protected, unusually large, unusually deep, or unusually compressed archives as higher-risk than ordinary attachments. Review any archive that contains executables, scripts, shortcuts, or files whose names and types do not match the sender context.
Common mistake: Teams often trust the extension or the first-layer scan result and stop there. That misses the inner payload, which is the part that matters operationally.
Practitioner takeaway: The right control objective is to understand what the archive becomes after extraction, because that is where delivery, staging, and exfiltration risk actually materialise.
Related resources from NHI Mgmt Group
- Guide: MITRE D3FEND Guide
- How do attackers turn a supply-chain incident into wider NHI compromise?
- How do attackers operationalise stolen OAuth tokens at scale?
- Why do attackers often check model availability before trying to generate content?
- How do attackers turn stolen npm secrets into broader compromise?