Malicious RTF — malware analysis report

Static analysis result for SHA-256 892859ea9d86fc44…

MALICIOUS

RTF

443.9 KB Created: 2018-04-04 08:54:00 First seen: 2020-02-04
MD5: c0f15436912d8a63dbb7150d95e6a4ee SHA-1: 0aee1fc554bfbb5150f65d424de551b77a1be974 SHA-256: 892859ea9d86fc441b24222148db52eb33cd106c2ac68eafbe83ab0064215488
282 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that exploits CVE-2017-11882 in the Equation Editor. This exploit is known to download and execute a second-stage payload from a remote URL. The extracted URL, http://www.google.com.d-dns.co/includes/686a0ea5/-1/1223/da897db0/final.hta, is highly suspicious and likely serves as the distribution point for the malicious payload.

Heuristics 8

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • 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.
  • ClamAV: Rtf.Exploit.CVE_2018_0802-6825822-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2018_0802-6825822-0
  • \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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.google.com.d-dns.co/includes/686a0ea5/-1/1223/da897db0/final.hta In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0006a2a1.bin rtf-objdata-decoded RTF \objdata at offset 0x6A2A1 9781 bytes
SHA-256: 6027b3d97923681dbf042473f050e8bf2c261e40c0d539ede260270c557166c8
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis found candidate code region(s). Indicators: SC_GETPC_CALL, NOP sled
objdata_01_off0006a2b4.bin rtf-objdata-decoded RTF \objdata at offset 0x6A2B4 35 bytes
SHA-256: e0f28ce3138172e7f0d29be00b7cfbd17d822420ce29f7663ca1be8ad04df92d

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