Office (OLE) / .XLS malware analysis — malicious · 99464d2fe2aa5abb

MALICIOUS

Office (OLE) / .XLS

280.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel

MD5: e57b0fec2bcc5e65fd5afd5a90a07aa3 SHA-1: 696cd7d64807e7830943bdccd95e7a2663b44c80 SHA-256: 99464d2fe2aa5abbfb5c8f51d90d0848b5fd6df3dde9d042d3f6b2bb6269ee03

180 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

The sample is an Excel spreadsheet containing Excel 4.0 macros, indicated by the OLE_XLM_AUTOOPEN heuristic. The document body and heuristics suggest a lure to impersonate DocuSign to trick the user into enabling macros (SE_ENABLE_LURE, SE_DOCUSIGN_LURE). The presence of the SC_STR_URLDOWNLOAD heuristic and the explicit mention of URLDownloadToFileA in the extracted artifacts strongly suggest that the macro's primary function is to download and execute a second-stage payload from one of the listed IP addresses. The macro also references 'ndll32', 'uRlMon', and 'RegisterServer', which are commonly associated with downloader or dropper functionalities.

Heuristics 5

Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD

Reference to URLDownloadToFile API
Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME

oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN

Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
Macro/content-enable lure medium SE_ENABLE_LURE

Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
Document signing service impersonation lure medium SE_DOCUSIGN_LURE

Document impersonates DocuSign, Adobe Sign, or a similar signing service in a signing-request context

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_macros.txt` `c64ff06c8727bfaca53241723c990851e8edfec13b22dbdad50cbbd6ce2e9aed`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	3545 bytes

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