Malicious PDF — malware analysis report

Static analysis result for SHA-256 b721e3329e9836b8…

MALICIOUS

PDF

83.5 KB Created: 2021-09-21 15:14:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 04b58489d959552d33f538e025ebf625 SHA-1: 61e81b83ba455f22c8bf89a56ce566b109cc7276 SHA-256: b721e3329e9836b889f591e745efff5bdd764691437e8341bc31ad8b2903c1e0
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or are hosted on disposable domains, indicating a link farm or SEO poisoning attempt. The ML classifier strongly flagged this PDF as malicious, and the presence of multiple external links suggests an intent to redirect users to potentially harmful content or further stages of an attack. No scripts were extracted, limiting the analysis of direct execution capabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 5

  • 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://allytemp.ru/uplcv?utm_term=how+to+view+blocked+numbers+on+android
    • http://codienlanhtrangia.com/Images_upload/files/48489794250.pdf
    • http://pk.mo/userfiles/file/63519400685.pdf
    • http://vipnovini.bg/root/f/uploads/files/45169351123.pdf
    • http://yenidenyuzlendirme.com/ckfinder/userfiles/files/kadikenekexufujimovaze.pdf
    • http://lifeline-sports.com/files/file/najixim.pdf
    • http://xy-interior.com/uploads/files/202109091010095256.pdf
    • http://www.workbythai.com/admin/assets/images/jamevigemojawavetaxekikiz.pdf
    • http://glttek.com/userfiles/file/72803303191.pdf
    • http://dlastudenta.org/Upload/file/53292696569.pdf
    • http://infinity-c-t.com/userfiles/file/bugowa.pdf
    • http://elvirajogsi.hu/ckfinder/userfiles/files/2604513368.pdf
    • http://hijoin.hu/editor_up/14678908256.pdf
    • http://yonseri.org/userfiles/files/64988049689.pdf
    • http://www.neoneofitou.com/ckfinder/userfiles/files/93873070308.pdf
    • https://taipeitccia.org/CKEdit/upload/files/46627797476.pdf
    • https://aquariumfargo.com/wp-content/plugins/super-forms/uploads/php/files/75a4a012ea8704e3e357bcef30874ac7/pexibusigevef.pdf
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/161407bc058b8b---28721398028.pdf
    • http://elitk.ru/_files/vorekabuwozibumifunepumix.pdf
    • https://www.grandeprairie.org/wp-content/plugins/formcraft/file-upload/server/content/files/161438ce0003a4---vepepewakigizok.pdf
    • https://izr.fr/files/40016876529.pdf
    • http://thsport.dk/userfiles/file/nejupumuzamelexujigig.pdf
    • http://raegcafe.com/uploads/files/54691278627.pdf
    • 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://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dfdc.bin
4fa4302c5086f47fd6b9ef5f12ec35fe8e019bb93eaac5cfa78b566b49f92eb1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDFDC 18284 bytes
font_01_sfnt_off00010f07.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10F07 16792 bytes
font_02_sfnt_off0001271e.bin
a098744ef6e46faae0a6558b37cb0c5cdd4d0c5974cf0881a680b756529cfed2		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1271E 11008 bytes

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