Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8631f23b48439f7…

MALICIOUS

PDF

77.7 KB Created: 2021-09-01 15:48:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 4aae2e126ee3b911c4b9b583704db92b SHA-1: 6d9196c6f46d8396e8d0dc968bbddfe993d5296e SHA-256: f8631f23b48439f74381346d3e734d9ad07d1810fe9e9f6c87f0237584ce96a0
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous URLs pointing to compromised WordPress upload directories. These links likely serve as a distribution point for further malicious content or phishing attempts. The presence of multiple compromised CMS upload links suggests a coordinated effort to host malicious files.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://israelonthehouse.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c75120a18e4---34582472569.pdf In PDF document text
    • http://rgjbreunion.com/clients/6/69/6950e03db8b1ea894755b369f0a03c31/File/nojod.pdfIn PDF document text
    • http://goksirkrupskimlyn.pl/img/upload/files/88681449760.pdfIn PDF document text
    • https://arnetbilgisayar.com/upload/ckfinder/files/razukudotuvojagadunopeda.pdfIn PDF document text
    • https://singaporeroadshow.com/wp-content/plugins/super-forms/uploads/php/files/5cfb949076c54ccabf39cd52072b7084/sidemiroxipevon.pdfIn PDF document text
    • http://brianhaymore.com/images/e/file/tofusumixu.pdfIn PDF document text
    • https://juhaszautovill.hu/userfiles/file/81096198714.pdfIn PDF document text
    • https://questyme.ca/userfiles/file/31558048572.pdfIn PDF document text
    • http://cisseo.net/userfiles/files/silikogitipom.pdfIn PDF document text
    • http://writtenmail.com/upload_images/file/8311162700.pdfIn PDF document text
    • http://cameronhaddock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cfe6045a9c---dewori.pdfIn PDF document text
    • http://montpellier-business-plan.fr/mbp/upload/images/images/upload/ckfinder/30849264716.pdfIn PDF document text
    • https://koffiewarenhuis.nl/app/webroot/files/userfiles/files/51844232888.pdfIn PDF document text
    • http://csc-0898.com/userfiles/file/20210613121152_ooghtz.pdfIn PDF document text
    • https://englewoodgrassfarm.com/wp-content/plugins/super-forms/uploads/php/files/bb1d4ab532e623590c594b326036242b/6530885769.pdfIn PDF document text
    • https://khanikango.in/file/20254233290.pdfIn PDF document text
    • http://training-solutions.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1609f0d92a74d7---mobituroxuzewox.pdfIn PDF document text
    • http://numismatika-nbkpdy.cz/userfiles/file/bilafebexutopav.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/09d38e3uqfk5br9sols3gcumh8/tavapenep.pdfIn PDF document text
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ad2dde29014---71776832546.pdfIn PDF document text
    • http://kursadowicz.pl/Upload/file/59461353879.pdfIn PDF document text
    • https://victory-agency.com/wp-content/plugins/formcraft/file-upload/server/content/files/160783331e25b3---zalaxatijilule.pdfIn PDF document text
    • http://frezerovka.by/images/fxeditor/file/lujejanil.pdfIn PDF document text
    • http://weilandensemble.nl/ckfinder/userfiles/files/duduvixezazejol.pdfIn PDF document text
    • https://designcoordinators.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607639884d797---74561501483.pdfIn PDF document text
    • https://pmeds.us/userfiles/file/5726804683.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=how+to+download+skins+on+osuPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cc0b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC0B 10280 bytes
SHA-256: e1b46dd1713d7fe60b91e4b67917cc607bf70109bcce591866a513c3bd91eb0b
font_01_sfnt_off0000e34b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE34B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fb5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB5D 17544 bytes
SHA-256: a64fb19c07e5a72f4cf351ee9768f9769dd9a0456698a3a814b387235370c6e3