Malicious PDF — malware analysis report

Static analysis result for SHA-256 b21cd7e2ad8fe8d0…

MALICIOUS

PDF

85.4 KB Created: 2021-09-02 17:28:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 005da5931fb88327d4118e30b3e329bb SHA-1: 226eb35ccbdc1346493dc03da4aaa2e5ee3be5bb SHA-256: b21cd7e2ad8fe8d034801ad6e1a24cb04e18b7e696c9d88342d8faeb8a94c50a
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to redirect users to potentially harmful content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

Heuristics 6

  • 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.
  • 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://www.freshstartdigitalmarketing.com/wp-content/plugins/super-forms/uploads/php/files/d982114d827d314fd0186505f43e9d7f/15995116522.pdf In PDF document text
    • http://frutapac.es/ckfinder/userfiles/files/jizexifasugoz.pdfIn PDF document text
    • https://gtnet-engine.com/ckfinder/userfiles/files/48152719652.pdfIn PDF document text
    • http://alpanelektrik.com/depo/sayfaresim/file/39413051400.pdfIn PDF document text
    • http://msci.com.ng/wp-content/plugins/formcraft/file-upload/server/content/files/160fc12274161e---pijifelezuluwixi.pdfIn PDF document text
    • http://topup-fight.com/ckfinder/userfiles/files/mojetagolonu.pdfIn PDF document text
    • http://hainescentreasia.com/images/file/87911400385.pdfIn PDF document text
    • http://beetsom.com/PROGRAM_FCKeditor_UserFiles/file/14015418260c42c0b0619e.pdfIn PDF document text
    • https://onlinendttraining.net/files/82354930971.pdfIn PDF document text
    • http://www.mezmat.ru/ckfinder/userfiles/files/wetusutolitu.pdfIn PDF document text
    • http://hotararicedo.ro/files/files/pebatagigujijulotibanedo.pdfIn PDF document text
    • https://gotamsui.com/ck_imgs/files/jegekotigegimave.pdfIn PDF document text
    • https://bouveau-consulting.com/userfiles/file/wibuxof.pdfIn PDF document text
    • https://kotata-zlin.cz/obr/clanky/file/faguwiximunotafilusul.pdfIn PDF document text
    • https://aiaciran.org/cache/fck_files/file/sanetepir.pdfIn PDF document text
    • https://sayurmateng.com/contents//files/39608934187.pdfIn PDF document text
    • http://elitvorota.ru/f/file/negateti.pdfIn PDF document text
    • http://dharmapremipariwar.org/userfiles/file/mufiwivop.pdfIn PDF document text
    • http://toanlinh.vn/upload/files/80456113275.pdfIn PDF document text
    • https://hospvetcentral.pt/site/upload/file/21883976793.pdfIn PDF document text
    • https://rowanmkt.com/Uploads/ckfinder/userfiles/files/gezebobutijujimegu.pdfIn PDF document text
    • https://arhstroi.by/uploads/files/tatode.pdfIn PDF document text
    • https://contabil-fiscal.ro/mm/file/fasava.pdfIn PDF document text
    • http://poorclarescork.ie/images/tonaledira.pdfIn PDF document text
    • https://tigercabinetry.com/wp-content/plugins/super-forms/uploads/php/files/39d7285a8f12bd933ae9af711658a8ad/somobapulepufewinokol.pdfIn PDF document text
    • http://www.theflightfest.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c3ad1d9d6d---tiponoxifegerugalirok.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=spyderco+triangle+sharpmaker+manualPDF 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_off0000e871.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE871 11340 bytes
SHA-256: 29e94e0568eb275af8cde6bc31f0e0e5e28466ef3f60486143759d651f861a42
font_01_sfnt_off000102b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102B7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011ac9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AC9 17212 bytes
SHA-256: 28931c84da0bf0a3be3ffe454e4f987ac7280b65504f817e92ec89903f2d93c1