Malicious PDF — malware analysis report

Static analysis result for SHA-256 88f975b61e9872dd…

MALICIOUS

PDF

82.7 KB Created: 2021-09-05 19:51:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 63184d9722a795ed02c99751b221a706 SHA-1: 1c140e16679407c50e7fc38edcb1571b535c72f7 SHA-256: 88f975b61e9872ddc96fee055a73a80fedc6fe7e016201a647e877fbe9591afe
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a link farm directing to multiple distinct hosts, many of which appear to be compromised CMS uploads or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to phish users or lead them to further malicious content. No scripts were extracted, and the document body was unreadable, but the heuristic findings are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://fastcomputer.vn/wp-content/plugins/super-forms/uploads/php/files/ba59345569c1d6c3a6e48e9ec58f20bf/48804918227.pdf In PDF document text
    • http://kaupa.cz/userfiles/file/kosob.pdfIn PDF document text
    • https://aquatim.ro/uploads/files/97662877330.pdfIn PDF document text
    • http://bong-dem-long.org/upload/editor/files/43118280231.pdfIn PDF document text
    • http://asude.istanbul/ck_images/files/48654526176.pdfIn PDF document text
    • https://www.vigo.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1608285183f1ea---zavudapaguwowom.pdfIn PDF document text
    • https://popa.com.br/wp-content/plugins/super-forms/uploads/php/files/f0c9a4047fb77fdfb3b6634b57cb5614/42390102542.pdfIn PDF document text
    • https://sunrise-photon.com/upfiles/editor/files/rusoxumobarejedewuliwasu.pdfIn PDF document text
    • http://library.nesdb.go.th/ic/admin/ckfinder/userfiles/files/94925575165.pdfIn PDF document text
    • https://alibabaoman.com/basefile/alibabaomancom/files/65804697545.pdfIn PDF document text
    • http://kondicionery-domodedovo.ru/upload_picture/file/xirexavuton.pdfIn PDF document text
    • http://alexhoffordphotography.com/temp/files/file/zubogewo.pdfIn PDF document text
    • https://ottopianos.nl/files/migaxaxusidawuvedido.pdfIn PDF document text
    • https://santa.sg/images/users/00000000/files/biwepunefofenugapuner.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609afb131dff9---ketogamuz.pdfIn PDF document text
    • http://www.garriagricola.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610415a544267---69829469415.pdfIn PDF document text
    • http://ophtalmic-overnight.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1609ac6f141448---pifowaredodugenojunuwupem.pdfIn PDF document text
    • http://sithome.com/upfiles/file/20210820200604.pdfIn PDF document text
    • http://www.pilonidalsinus.gen.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1608459658d786---tojenoravepipodofeseri.pdfIn PDF document text
    • http://www.hollyskauaicondo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160804b485cab7---detizerizam.pdfIn PDF document text
    • http://splhardware.com/UploadFile/file/2021080820581073499.pdfIn PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160deee6161a85---3887919695.pdfIn PDF document text
    • http://www.louthadventures.ie/wp-content/plugins/formcraft/file-upload/server/content/files/1608a48052204c---31731496929.pdfIn PDF document text
    • https://sg-design.top/wp-content/plugins/super-forms/uploads/php/files/5acb64bb0e79992f16bea45c0e8fbd9e/vexawulobojinunukagupu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=language+level+test+pdfPDF 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_off0000de52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE52 17900 bytes
SHA-256: 6e421321fb1d80b59e1fe6f24e4b0862797e22eb0d84a9a81898d4bb089b7d48
font_01_sfnt_off00010cff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CFF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012516.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12516 10484 bytes
SHA-256: 42bd5f789c1068dcb2b4668951b08d74632413619ff5c473e0f1b41f1b91a207