CVE-2015-2545 is a malformed EPS file vulnerability in Microsoft Office. CISA added it to the Known Exploited Vulnerabilities catalogue on 3 March 2022, which means attackers have used it in real attacks. Microsoft Office allows remote attackers to execute arbitrary code via a crafted EPS image.
What the vulnerability is and why it matters
CVE-2015-2545 is a malformed EPS file vulnerability in Microsoft Office that can let an attacker trigger arbitrary code execution through a crafted image. In practice, that means a document can become a delivery vehicle for remote code execution if a user opens it in a vulnerable environment.
The danger is not the EPS format by itself, but the trust Office places in embedded content that appears harmless. Office documents are often exchanged through email, collaboration platforms, and shared drives, so a single malicious file can reach many users quickly.
How exploitation usually happens
This vulnerability class is dangerous because it abuses document parsing, not user-installed macros. An attacker only needs a booby-trapped file that causes Office to process the malformed EPS content during normal document handling.
That makes the attack path appealing for phishing, drive-by delivery, and targeted intrusion. Once code execution is achieved, the attacker can move from document opening to broader host compromise, often before the user notices anything unusual.
For background on how Microsoft Office fits into the wider Windows security surface, see the Microsoft 365 Security Guide, which covers hardening measures around the Office ecosystem.
Exposure checks and remediation priorities
Organisations should start by identifying where Microsoft Office is installed, which users routinely handle external documents, and which endpoints can open untrusted attachments. Exposure is highest where email gateways, download portals, or file-sharing workflows permit unsolicited Office documents to reach users.
For version and authoritative record details, rely on the CVE Program and the NIST National Vulnerability Database rather than reproducing patch specifics from memory. The right remediation path depends on the exact product build, deployment model, and vendor guidance.
Where patching cannot be completed immediately, reduce exposure by limiting unsolicited document handling, strengthening attachment controls, and using endpoint protections that can block suspicious child processes, script launch, or document-based exploitation. Risk-based prioritisation should treat internet-facing or heavily exposed user populations as the first remediation tier.
For a structured remediation workflow, the Vulnerability Management Guide is useful for asset scoping, KEV prioritisation, and verification after remediation.
Detection and post-exploitation review
Detection should focus on suspicious Office activity around the time a malformed EPS file is opened, especially unexpected process spawning, unusual child applications, or follow-on network activity that does not fit the user’s normal workflow. Because exploitation can lead directly to code execution, defenders should look beyond the document itself and review host telemetry for post-open behaviour.
After patching, assume the system may still require compromise review if the file was opened before remediation. That review should include the endpoint, associated mailbox or download source, and any accounts, sessions, or credentials exposed on the host after execution.
When malicious document parsing is part of the intrusion path, the next steps are often lateral access, credential theft, or persistence. A compromise review should therefore check for secondary malware, new autoruns, and any evidence that the attacker moved beyond the original Office process.
Risk and Threat Considerations
Malformed document vulnerabilities are especially risky because they turn a routine productivity action into an execution event. In an Office environment, that creates a direct path from file opening to host compromise, which is why these issues remain attractive to attackers and are frequently included in real-world exploit campaigns.
Failure mechanism: The application parser accepts attacker-controlled EPS content and mishandles it in a way that enables arbitrary code execution under the victim’s context.
Impact: Successful exploitation can lead to endpoint compromise, malware deployment, credential exposure, and follow-on intrusion activity across the environment.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5 and CIS Controls v8 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | SI-3 — Malicious Code Protection | Office EPS exploitation is a malicious-code delivery path. |
| SI-4 — System Monitoring | Exploit detection depends on monitoring post-open process and network behavior. | |
| RA-5 — Vulnerability Monitoring and Scanning | KEV-listed CVEs require inventory-driven exposure tracking and remediation prioritization. | |
| Recommendation — Block and inspect malicious document content before it reaches endpoints. Monitor Office and endpoint activity for exploit indicators and suspicious child processes. Continuously identify affected assets and prioritize remediation for KEV-listed vulnerabilities. | ||
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | This CVE needs asset inventory, exposure review, and prioritized remediation. |
| CIS-10 — Malware Defenses | EPS exploitation is a malware delivery and execution concern. | |
| Recommendation — Track exposed Office assets and remediate exploited vulnerabilities on a risk basis. Use malware defenses to block or contain malicious Office document activity. | ||
Practitioner Guidance
Why practitioners should care: This is not just a patching issue, it is a document trust issue. If your organisation routinely opens externally sourced Office files, the blast radius includes users, endpoints, and any secrets or sessions available on the compromised machine.
What to watch for: Treat unexpected EPS handling, suspicious child processes from Office, and document-originated alerting as escalation signals. If the file was received externally and opened before remediation, validate the endpoint for post-exploitation activity even if the user reported no obvious symptoms.
Practitioner takeaway: Prioritise exposure reduction, not only patch deployment, because document-based code execution often arrives through ordinary business workflows rather than obvious malicious infrastructure.
Related resources from NHI Mgmt Group
- CVE-2015-1770 (Microsoft Office Uninitialized Memory Use)
- How should organisations give AI agents safe read and write access to Microsoft Office files without building custom file-handling infrastructure?
- CVE-2009-0238 (Microsoft Office Remote Code Execution)
- CVE-2026-21509 (Microsoft Office Security Feature Bypass)