Malicious PDF — malware analysis report

Static analysis result for SHA-256 81fd4f640ad92c5e…

MALICIOUS

PDF

77.4 KB Created: 2021-09-26 19:58:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: f90d160b87c624c124150c2568fe7540 SHA-1: e6dcceb3e534945f177630d7da97679d9e438347 SHA-256: 81fd4f640ad92c5e62dd8b500687e42ee741241e8cdb0271970c69fab0b9cb98
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to disposable or compromised hosting, suggesting a phishing or malware distribution scheme. The presence of numerous unknown URLs further supports this, as they likely lead to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9829

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://ketex.com/trcgp/ckfinder/userfiles/files/15295809693.pdf In PDF document text
    • http://nextgenship.net/upload/file/2021090116305266530.pdfIn PDF document text
    • https://www.generalutilities.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139b2691ef40---87700956733.pdfIn PDF document text
    • https://parvazyab.com/basefile/api203/files/kumozaluwomaremudosifo.pdfIn PDF document text
    • http://cnzgks.com/userfiles/file///dowomikugiruwutos.pdfIn PDF document text
    • https://domilot.com/uploader/files/pazavagaxalefebunavu.pdfIn PDF document text
    • http://taemyung.com/data/upload/file/xowakanejeremop.pdfIn PDF document text
    • http://cgt-fo-csc.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16142aa2479a72---2313092533.pdfIn PDF document text
    • http://amy-tsai.com/images_express/userfiles/files/nirepabavatugivexupitus.pdfIn PDF document text
    • http://azinsaghf.com/cache/fck_files/file/tenadopowunidezu.pdfIn PDF document text
    • https://retta-bg.com/userfiles/76414709837.pdfIn PDF document text
    • http://absolutelyneon.com/userfiles/file/94197517298.pdfIn PDF document text
    • http://hsi-international.com/ckfinder/userfiles/files/zifitavetupipasovat.pdfIn PDF document text
    • https://www.unicodesystems.com/wp-content/plugins/super-forms/uploads/php/files/s81q9l923ovoaag23ehduqqlh4/pubenuduxix.pdfIn PDF document text
    • http://kythuatviet.vn/uploads/userfiles/file/42629219337.pdfIn PDF document text
    • https://tele-video.ru/upload/files/33943101553.pdfIn PDF document text
    • https://xenang-mitsubishi.com/fckupload/file/57890554628.pdfIn PDF document text
    • http://tourhong.com/FileData/ckfinder/files/20210909_85939D8FFFDA6397.pdfIn PDF document text
    • http://tidomusica.com/uploads/files/202109171437542180.pdfIn PDF document text
    • https://www.fifatravels.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614d0747b5771---84620754032.pdfIn PDF document text
    • http://www.kymenhome-etsinta.net/tiedostot/files/patomugemobe.pdfIn PDF document text
    • https://pikhospital.com/ck_uploads/uploads/files/gasujalivolumul.pdfIn PDF document text
    • http://dh-cell.net/ckfinder/userfiles/files/lonoveziguzunowet.pdfIn PDF document text
    • https://domilot.com/uploader/files/10594007436.pdfIn PDF document text
    • http://deeringbayrealestate.com/userfiles/files/kuzajulasagovoxe.pdfIn PDF document text
    • https://sealand-pptc.com/userfiles/file/40742623293.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=magic+call+apk+modPDF 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_off0000c45f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC45F 20360 bytes
SHA-256: cf2ee846270ecc5c48185288f6347f72475d06e0d4e9bdf1649240b579fae22c
font_01_sfnt_off0000f917.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF917 10340 bytes
SHA-256: 43576f558c8ac70faacc709c676f5affa2e6f8b3160e5686b24ececc0b551722
font_02_sfnt_off00011030.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11030 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1