Malicious PDF — malware analysis report

Static analysis result for SHA-256 7a661373eb95d54d…

MALICIOUS

PDF

115.1 KB Created: 2021-07-24 21:27:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 997c32fecf64fe1ca55718edea15e556 SHA-1: f5318cd34e4a65cbf89e2b9930df90dff6ce9d2f SHA-256: 7a661373eb95d54d2c7c7d926015b375a5127cb0a23b198c1e3c310e7ae00dc4
176 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, with heuristics indicating it is a link farm and a callback phishing lure. The document body is heavily obfuscated, but the presence of multiple external URIs and the 'SE_CALLBACK_LURE' heuristic strongly suggest a phishing or scam attempt designed to trick the user into initiating a phone call. No scripts were extracted, but the PDF structure itself likely contains exploit code.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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 http://tygodnikzuzlowy.pl/ckfinder/userfiles/files/supepinofuxete.pdf In PDF document text
    • http://amexeuro.com/an3_Uploads/file/rapawasinefavapo.pdfIn PDF document text
    • https://lightupalife.org.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1608257d80513c---90825388531.pdfIn PDF document text
    • http://bestforfishing.com/wp-content/plugins/super-forms/uploads/php/files/6d94660d4fc841470ad00bdf2dac9bf6/biribis.pdfIn PDF document text
    • http://www.eflox.net/wp-content/plugins/formcraft/file-upload/server/content/files/16099be26ab83d---xuwovif.pdfIn PDF document text
    • https://sinhadventure.com/uploads/file/10336964706.pdfIn PDF document text
    • http://healthywithhart.com/res/file/43603855093.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16080d9d415e66---mizubodul.pdfIn PDF document text
    • http://oreade-breche.fr/userfiles/file/13212008898.pdfIn PDF document text
    • https://krono-original.vn/Images_upload/files/fosujufugijisuvaxaxonavi.pdfIn PDF document text
    • https://trellisdundee.com/wp-content/plugins/super-forms/uploads/php/files/6aff8ec9b0f269051828b32edb9154cc/kupupodepigidufafal.pdfIn PDF document text
    • https://journeypeople.cc/wp-content/plugins/super-forms/uploads/php/files/1de7ffd09e12c1c4929b918cdbba1d82/89032721380.pdfIn PDF document text
    • https://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/1991c1e6570a494c11c6cba578274e67/kalixumadojox.pdfIn PDF document text
    • http://co-mit.com/uploads/files/vuzapogaketavimusuxuzolu.pdfIn PDF document text
    • http://lohsclassof70.com/clients/3/31/31ca850ff086a58b81c8700e10a01852/File/vaxasevetusomu.pdfIn PDF document text
    • http://jointrilogy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084f6592c2b9---2361083541.pdfIn PDF document text
    • https://wlao.on.ca/wp-content/plugins/super-forms/uploads/php/files/63529e21ce5a63477cb2f1ece1f1ebdb/7303795682.pdfIn PDF document text
    • http://chiangmai-clean.com/user_img/files/woravevokob.pdfIn PDF document text
    • http://daimarconstrucciones.com/images/admin/file/gekilofa.pdfIn PDF document text
    • http://botosani.ro/img/uploads/file/jifukapisibodo.pdfIn PDF document text
    • http://www.look4job.gr/images/_user_na/file/79849944524.pdfIn PDF document text
    • http://lezeckastenakosice.sk/upload/files/87029695382.pdfIn PDF document text
    • http://ylpqzl.com/ckfinder/userfiles/files/84392525370.pdfIn PDF document text
    • https://bbensonmft.com/wp-content/plugins/super-forms/uploads/php/files/bc80b307ebec3802deac6eb439962a6d/vifijovilor.pdfIn PDF document text
    • https://www.hospedeagora.com.br/wp-content/plugins/super-forms/uploads/php/files/61u7i8qqo8uud1ttkfe1a8rmt0/refifodutexokewonivezajep.pdfIn PDF document text
    • https://www.marvistasales.com/wp-content/plugins/super-forms/uploads/php/files/a457fa1532e8385ac6c79dea975ebf28/vizaxosibapafutus.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=terraria+calamity+base+downloadPDF link annotation
    • 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_off000163ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x163EA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00017c01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17C01 10836 bytes
SHA-256: 8ab9f087514a269595995fff58848694cc3535a6bc40ae515a529f0119ddc590
font_02_sfnt_off0001950c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1950C 17840 bytes
SHA-256: 2640e68983b4bb7dc29287ae1b206fe1e251830924ad713e1d45f855af6d0e66

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