CVE-2015-1770
Microsoft Office Uninitialized Memory Use Vulnerability
Description
CVE-2015-1770 is a critical remote code execution vulnerability (CWE-908) in Microsoft Office that arises from the use of uninitialized memory during the processing of specially crafted Office documents. An attacker can exploit this flaw by sending a malicious document to a victim, and if the victim opens it, the attacker can execute arbitrary code with the privileges of the current user. CISA has confirmed active exploitation and added CVE-2015-1770 to the Known Exploited Vulnerabilities catalog. With an EPSS score of 78.2% (99.6th percentile), this vulnerability is a severe threat for organizations relying on Microsoft Office.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | office | 2013 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://www.securityfocus.com/bid/75016(Broken Link, Third Party Advisory, VDB Entry)
- http://www.securitytracker.com/id/1032523(Broken Link, Third Party Advisory, VDB Entry)
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-059(Patch, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-1770(US Government Resource)
Weakness Type
CWE-908: Use of Uninitialized Resource
CWE-908 describes a weakness where software uses a resource that has not been properly initialized, leading to undefined behavior that may include information disclosure, crashes, or arbitrary code execution. In CVE-2015-1770, Microsoft Office accesses uninitialized memory during document processing, allowing an attacker to control the contents of the uninitialized memory region and redirect execution to arbitrary code.
Learn more: CWE-908 — Use of Uninitialized Resource
Impact Analysis
CVE-2015-1770 is exploitable by sending a specially crafted Office document to a victim via email, file sharing, or web download, requiring the user to open the document. Successful exploitation grants the attacker code execution with the privileges of the user running Office, which in many enterprise environments includes access to sensitive documents, email, network shares, and internal applications. Confidentiality is fully compromised as the attacker gains the ability to read all data accessible to the victim. Integrity and availability are equally impacted through malware installation, data modification, and potential ransomware deployment. The 99.6th percentile EPSS score reflects very high exploitation probability, particularly through targeted spear-phishing campaigns.
Exploit Maturity
CVE-2015-1770 is confirmed as actively exploited in the wild by CISA and is listed in the Known Exploited Vulnerabilities catalog. The EPSS score of 78.2% (99.6th percentile) indicates very high real-world exploitation probability. Office document-based exploits are particularly effective in targeted attacks because they leverage the trust users place in document formats and can bypass network-level security controls by arriving through legitimate email channels.
Remediation
- Apply the Microsoft security update MS15-059 (June 2015) for Microsoft Office to address CVE-2015-1770 immediately on all affected systems.
- Enable Protected View and Application Guard for Office to sandbox document rendering and prevent automatic execution of exploits in untrusted documents.
- Deploy email gateway filtering to scan and quarantine suspicious Office documents before they reach end users, particularly documents from external senders.
- Educate users about the risks of opening unsolicited Office documents and implement policies requiring verification of unexpected attachments.
- Keep Microsoft Office updated to the latest supported version and consider migrating to Microsoft 365 for continuous security updates and enhanced threat protection features.
Technical Details
CVE-2015-1770 is an uninitialized memory use vulnerability (CWE-908) in Microsoft Office that occurs during the parsing of specially crafted document structures. When Office processes certain document elements, it allocates memory for internal data structures but fails to properly initialize all fields before use. An attacker can craft a document that manipulates the heap state such that the uninitialized memory region contains attacker-controlled data, which is then used as a function pointer or object reference. By carefully arranging the heap layout through heap spraying or other memory manipulation techniques, the attacker can direct program execution to shellcode and achieve arbitrary code execution within the Office process context.
Frequently Asked Questions
Is CVE-2015-1770 being actively exploited?
Yes. CVE-2015-1770 is confirmed as actively exploited in the wild by CISA and is listed in the KEV catalog. The EPSS score of 78.2% (99.6th percentile) reflects very high real-world exploitation probability, particularly through targeted phishing campaigns using malicious Office documents.
What products are affected by CVE-2015-1770?
CVE-2015-1770 affects Microsoft Office 2007, Office 2010, Office 2013, and Office 2013 RT. The vulnerability is present in the core Office components responsible for document processing and rendering.
How do I fix CVE-2015-1770?
Apply the Microsoft security update MS15-059 (June 2015) for Microsoft Office on all affected systems. Enable Protected View for documents from untrusted sources, and deploy email filtering to block suspicious Office documents.
How severe is CVE-2015-1770?
CVE-2015-1770 is rated CRITICAL and allows full remote code execution through a malicious Office document. The 99.6th percentile EPSS score and CISA KEV listing confirm this is a high-severity vulnerability that is actively exploited in real-world attack campaigns.
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