Malicious RTF — malware analysis report

Static analysis result for SHA-256 13a40dc279731226…

MALICIOUS

RTF

1.85 MB
MD5: 5ce89c7ad0bba4d0b3b76f4dca5faba5 SHA-1: d5ab282e0d72876343d52d552e2507c00701a985 SHA-256: 13a40dc279731226ec6f067736c3d5fa54ed0a66cb8358f1dd489e988c4959bd
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains multiple indicators of malicious activity, including embedded OLE objects and specific firings for RTF_EQUATION_EDITOR and CVE_2017_11882_RELATED. These heuristics strongly suggest the exploitation of CVE-2017-11882, a known vulnerability in Microsoft Equation Editor, to achieve code execution. The presence of a large, decoded OLE object further supports the likelihood of a hidden payload being delivered.

Heuristics 6

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1934KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000c2.bin
eb53e3f7fd8ec98afca47be319941cfe4d61b9c6823fa6baca3570d1ef51d276		 rtf-objdata-decoded RTF \objdata at offset 0xC2 967184 bytes

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