Malicious PDF — malware analysis report

Static analysis result for SHA-256 13733e03027bc4f3…

MALICIOUS

PDF

86.0 KB Created: 2021-08-11 13:42:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: ba94aae6afeec55a4f989340d92195a5 SHA-1: 9b1b2e2bba8aac498b4239f9504aa5da90250307 SHA-256: 13733e03027bc4f3d4b0980ed7e6c18a10192c23ecfb0fe4369cbd338e73dccd
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 a machine learning classifier and ClamAV, indicating a phishing or trojan payload. It functions as a link farm, with numerous embedded URLs pointing to compromised WordPress sites and disposable domains, likely intended to lure users to malicious content. The document body is heavily obfuscated and unreadable, providing no direct clues to its specific purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9919

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://cructi.ru/uplcv?utm_term=cutting+edge+upper+intermediate+tests+pdf PDF link annotation
    • http://basumati.com/app/webroot/ckfinder/userfiles/files/92780223310.pdfIn PDF document text
    • https://www.arphplumbing.co.uk/wp-content/plugins/super-forms/uploads/php/files/kqldell968fd0qcui55tj9eer4/64826575782.pdfIn PDF document text
    • https://jdbailbonds.com/wp-content/plugins/super-forms/uploads/php/files/f07341df6ed997e0bc6493f1f3dc2eca/lonofumizezikelimugi.pdfIn PDF document text
    • http://securitydirect.it/wp-content/plugins/super-forms/uploads/php/files/0c23966269acc82bfaedce9a3006a8b4/50325302089.pdfIn PDF document text
    • http://videoacceso.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cd67da8500a---61209115874.pdfIn PDF document text
    • http://call.ae/wp-content/plugins/formcraft/file-upload/server/content/files/1607aa0ec2af23---fipuxala.pdfIn PDF document text
    • http://avtoarka.ru/wp-content/plugins/super-forms/uploads/php/files/92dca500139797047f41235cc9b98c76/sezobunat.pdfIn PDF document text
    • http://bike-aholic.com/UserFiles/file/4131182047.pdfIn PDF document text
    • https://www.pharmaright.ca/wp-content/plugins/super-forms/uploads/php/files/8833oe7mjk2c2o3hd0toddr1si/bafad.pdfIn PDF document text
    • https://www.nobleorthodontic.com/wp-content/plugins/super-forms/uploads/php/files/8ed3df72d415076a726fe6ffee1aec21/17985325189.pdfIn PDF document text
    • https://atolab.it/wp-content/plugins/super-forms/uploads/php/files/84ee19bd31986112d8ba3a4cee5a70e0/liwapusonijutosukojedot.pdfIn PDF document text
    • http://el-master.ru/userfiles/file/kexelunurizipufemikero.pdfIn PDF document text
    • https://www.fifatravels.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bb710729d4b---wolikoj.pdfIn PDF document text
    • http://voyagevietnamlaos.com/hinhanh/file/24323074688.pdfIn PDF document text
    • https://tahitotfalu.hu/ckfinder/userfiles/files/rijunejonozitasebudusiwis.pdfIn PDF document text
    • http://abpaluso.com/upload/file/dulakorakelulonatadekapik.pdfIn PDF document text
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/160de1848cb839---tekadekun.pdfIn PDF document text
    • https://vakukh.ru/wp-content/plugins/super-forms/uploads/php/files/43602f4ded6bf022d0a3eb5bb3e30cec/tipofesodefoxufim.pdfIn PDF document text
    • https://www.sidertest.it/wp-content/plugins/formcraft/file-upload/server/content/files/160792dd503a5e---widonifuvumogilixi.pdfIn PDF document text
    • https://profbuhotchet.ru/wp-content/plugins/super-forms/uploads/php/files/55568aa52cb893e516c563b3bb466197/folebufizagadaledev.pdfIn PDF document text
    • https://caravanandre.it/wp-content/plugins/super-forms/uploads/php/files/e512ed221b8ce77823bcce5b667fcd1c/didefegidedavetepevo.pdfIn PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/607d5a2b73a758022172719f8c8afc61/gugudonisexirosajaditu.pdfIn PDF document text
    • https://kawanmto.info/contents//files/naloxapekolivuga.pdfIn PDF document text
    • http://partnerplus30.ru/images/fornews/files/nariwijukotexagolijebur.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16095203113c35---gunovoxevalatujivi.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/160e97bf27777a---36389104356.pdfIn PDF document text
    • 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_off0000e4d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4D4 20628 bytes
SHA-256: 0d7b3443cab8ea729c6aa263968f1aafd2ce0f3ea36cc5961104c01daae77f8f
font_01_sfnt_off00011895.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11895 10808 bytes
SHA-256: f14e325c3f1555d65a1bce68297d69f51dd5e06c68c136866af811aba1e4466a
font_02_sfnt_off0001314f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1314F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1