Malicious RTF — malware analysis report

Static analysis result for SHA-256 bef44d5d5062f50c…

MALICIOUS

RTF

28.7 KB First seen: 2018-12-09
MD5: a7e5aab16e50c64163becc0d8fc467aa SHA-1: 0266eb72b43bffb3f4b784ea794142f0e26f6309 SHA-256: bef44d5d5062f50c6530052d6c802e91a91f08f1c9a6520403f35f1980923e5b
220 Risk Score

Malware Insights

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

The sample is an RTF document that contains an OLE object. Heuristics indicate a critical vulnerability, CVE-2017-11882, which is known to be exploited for client execution. This exploit likely facilitates the execution of a secondary payload, making spearphishing attachment a probable initial access vector. No specific family could be identified.

Heuristics 5

  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Doc.Exploit.CVE_2017_11882-6934206-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.CVE_2017_11882-6934206-0
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003f.bin rtf-objdata-decoded RTF \objdata at offset 0x3F 4135 bytes
SHA-256: 9d2432bd6a865bff4aa0fd4b20eb4fd82122d2016d9f61b12b96f8ed1e6577fb