Xls.Downloader.94c25b356b5a6cac-9978798-0 — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 77c701efea15f393…

MALICIOUS

Office (OLE) / .XLS

1.43 MB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2023-02-14
MD5: 1c5cb4dd84f8741db473c5913abc7ab8 SHA-1: 87576690b7ff879759cd781b78ed7c1fd7368b76 SHA-256: 77c701efea15f393c9fb5d3c5b2e39a505c7ba856c2264f9ee5f684288dc2c88
208 Risk Score

Malware Insights

Xls.Downloader.94c25b356b5a6cac-9978798-0 · confidence 95%

MITRE ATT&CK
T1204.002 Malicious File T1566.001 Spearphishing Attachment

The critical heuristic firing for CVE-2017_11882_EQUATION_OLE10NATIVE indicates the exploitation of a known vulnerability in Microsoft Equation Editor. This, combined with the ClamAV detection as a downloader, strongly suggests the file's purpose is to exploit this vulnerability to download and execute a secondary payload. No VBA macros were found to contain executable statements, but the embedded OLE object is the primary vector.

Heuristics 5

  • Equation Editor Ole10Native payload — CVE-2017-11882 critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE
    An embedded Microsoft Equation 3.0 object (CLSID 0002CE02-0000-0000-C000-000000000046) carries an Ole10Native packager stream instead of the normal Equation Native/MTEF data. This is the weaponized Equation Editor RCE delivery shape used by CVE-2017-11882 / CVE-2018-0802 maldocs. The payload (font-record overflow + shellcode) is frequently encrypted and the stream name case-scrambled to evade scanners, but an Equation object holding an Ole10Native stream has no benign use.
  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Contains Equation Editor object — related to CVE-2017-11882 / CVE-2018-0802 exploitation, but CLSID presence alone is not the malformed MTEF exploit primitive.
  • ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.94c25b356b5a6cac-9978798-0
  • x86 GetPC stub (CALL $+5; POP EBX) high SC_GETPC_CALL
    x86 GetPC stub (CALL $+5; POP EBX)
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
7f506327609c082af1cd37dde23bc2c71a000f7d1ef530b6abb66775040a7673		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1206 bytes
ole10native_00.bin
986d20143e68a8eacddebaf895925b4d6296c03d21f28e210af035e2e3a2c59b		 ole-package OLE Ole10Native stream: MBD012CBF8D/oLe10nATiVE 1420 bytes

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