Malicious PDF — malware analysis report

Static analysis result for SHA-256 55f4fec16a947334…

MALICIOUS

PDF

71.6 KB Created: 2021-04-01 14:33:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 8aa27de765fd8f36633abb936fd9a1bf SHA-1: d796b2403d9093493624f08e7bbb5f057d7766ef SHA-256: 55f4fec16a947334abcaeb986e7b2b57fe1be251702664864b5f902f54ab8a4d
164 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which are disguised as download opportunities. The 'PDF_SEO_LINK_FARM' heuristic indicates a deliberate attempt to create a link farm, and the 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' heuristics confirm its malicious nature. The primary IOC is the initial URL used to host the link farm, which likely serves as a lure for further malicious downloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 6

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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 https://lozipotod.ru/award?keyword=issuu+download+pdf+file
    • https://cdn-cms.f-static.net/uploads/4498366/normal_60184b4c5a9d9.pdf
    • http://vozuzutiwajuzip.getenjoyment.net/madjax_rear_seat_kit_club_car_precedent.pdf
    • http://tejasatobes.medianewsonline.com/how_to_answer_nclex_pn_style_questions.pdf
    • https://cdn-cms.f-static.net/uploads/4375340/normal_603bc8017898c.pdf
    • https://cdn-cms.f-static.net/uploads/4455898/normal_60407ee49ab80.pdf
    • http://wozuxel.getenjoyment.net/sepudawifam.pdf
    • https://static.s123-cdn-static.com/uploads/4416496/normal_5ff9266e48908.pdf
    • https://static.s123-cdn-static.com/uploads/4474206/normal_5fe4bdf843469.pdf
    • https://cdn-cms.f-static.net/uploads/4365580/normal_6010f80224fe0.pdf
    • http://nejevefivi.mypressonline.com/pesirotorebutekisitib.pdf
    • https://cdn-cms.f-static.net/uploads/4425929/normal_603bf89c59206.pdf
    • https://cdn-cms.f-static.net/uploads/4387704/normal_6040e339e5cdb.pdf
    • https://static.s123-cdn-static.com/uploads/4421208/normal_5ff9bc4612912.pdf
    • http://rawitotizoxuk.scienceontheweb.net/24312095233.pdf
    • https://cdn-cms.f-static.net/uploads/4530457/normal_6044774a755f1.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://ac685e6e-6442-44c0-91a1-b3a367e79ef2.filesusr.com/ugd/ce77c6_e6f68e8c343b4b968553aac9ce1164be.pdf?index=true
    • http://vavadot.onlinewebshop.net/david_copperfield_penguin_readers_level_3.pdf
    • http://gumomexad.onlinewebshop.net/84061641023.pdf
    • https://3caa4030-7dd6-4be4-8a8a-e1981c45b3cd.filesusr.com/ugd/704988_093460da2b8c48ebb4e44d41a3f80366.pdf?index=true
    • https://4c80ca50-31de-4e6f-b265-471620011c4a.filesusr.com/ugd/08c6b7_cfc1d2521acc4ab0ba6284a85d1caaff.pdf?index=true
    • https://cc6d8859-fc08-4100-a073-55b48c5addfc.filesusr.com/ugd/238140_a02f8677e63d4e7db6599338d9f466d3.pdf?index=true
    • https://54179944-c6a3-49b3-9462-5d1939b6aff2.filesusr.com/ugd/49f5ef_329e3f1fe9e648c6a50359b41e82dcae.pdf?index=true
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dd34.bin
80baf2f0ba3260b47dd648ec2436fdf0ffae4fa936bbcfedf46bfdc20053aba4		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDD34 4968 bytes
font_01_sfnt_off0000ee46.bin
406e894363ad56419477d66d584947a0a867afbb333809e8adb35896a92565db		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEE46 10388 bytes

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