Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a35adc86841a3ce…

MALICIOUS

PDF

90.5 KB Created: 2021-07-31 12:26:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: a6596f05f29ed51bbe8dc7810579b594 SHA-1: 2b9ed4c594820a1ce03e37d6130e4f60af8f95e6 SHA-256: 4a35adc86841a3cedf46e87493153e5afdae692d3abb1dd97c6cb7b7a620f79f
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many of which point to compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or SEO spam. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://seataclightingalaska.com/wp-content/plugins/super-forms/uploads/php/files/73c7e1ac0f7d996816400b01b26b9701/modol.pdf In PDF document text
    • http://biurod9.pl/public/userfiles/file/77659211379.pdfIn PDF document text
    • https://houstoncoinshow.org/FCKeditor/file/xigurujobisinix.pdfIn PDF document text
    • http://pericosrentcar.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1609074a7b366e---goretogujumexomugumi.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f454d293a86---vobujujekimunasurupoj.pdfIn PDF document text
    • http://mid-europe-ex.com/images/blog//file/rovoxibubupirixelele.pdfIn PDF document text
    • https://ercrs.org/wp-content/plugins/super-forms/uploads/php/files/dve1jrmtlr71r5qqgsbqlsmvi1/nefolagikutapagebudaweju.pdfIn PDF document text
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1609325e159e14---xekuwewotonijajejodupopej.pdfIn PDF document text
    • https://fietenhaardenenkachels.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160c4e7962a9cc---jotapelami.pdfIn PDF document text
    • http://elmiraclassiccountry.com/wp-content/plugins/super-forms/uploads/php/files/o7fovf05bfunct627f242ukpj3/zewixese.pdfIn PDF document text
    • https://accuratesearch.com/userfiles/file/70562127853.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-7-14/20210714130000416920.pdfIn PDF document text
    • http://schoonhovensvrouwenkoor.nl/ckfinder/userfiles/files/lororonuterasirur.pdfIn PDF document text
    • https://wecafephuket.com/wp-content/plugins/super-forms/uploads/php/files/h4f0at9ujgbgbhjcmmei82dhi0/34604016866.pdfIn PDF document text
    • http://axwelindia.com/uploads/52279057353.pdfIn PDF document text
    • http://villaturri.it/wp-content/plugins/formcraft/file-upload/server/content/files/16089fe9fe9f65---51880513768.pdfIn PDF document text
    • https://bestrecycledautoparts.net/images_i/file/29196270962.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/160758b9c7eea0---97249182846.pdfIn PDF document text
    • https://www.shopveriamici.com/wp-content/plugins/super-forms/uploads/php/files/umptrgo6mmpqor5jdq7n6nv9u4/xopoji.pdfIn PDF document text
    • https://zweiund40.com/wp-content/plugins/super-forms/uploads/php/files/n50b3sj59mpov78mn5enc8j8uo/26741053340.pdfIn PDF document text
    • https://www.syah.org/wp-content/plugins/super-forms/uploads/php/files/e596f1610a00a493e83d195c331f3597/kawivasunejuvate.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085c3efe5e4c---ririvobokaxe.pdfIn PDF document text
    • https://xn--faade-zra.ch/ckfinder/userfiles/files/19530224904.pdfIn PDF document text
    • http://yishiweb.com/upfiles/files/20210602_001402.pdfIn PDF document text
    • http://elonsummerstorage.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c12eed16a42---57335445445.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=what+is+the+best+essential+oil+reference+bookPDF 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_off0001003c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1003C 10656 bytes
SHA-256: 9aea8acb6d3c2d4c0227bed6a6d92de1b5e55e4d0bd4efcd17ec9dd6376001d5
font_01_sfnt_off0001189d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1189D 16780 bytes
SHA-256: 3b361a8b64c675a936bd998431831c5377b80da1ddf1c228a5f92c7734872834
font_02_sfnt_off0001438f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1438F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1