Malicious PDF — malware analysis report

Static analysis result for SHA-256 16cf52b4683b36c3…

MALICIOUS

PDF

80.4 KB Created: 2021-08-21 23:34:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-18
MD5: b956aae43129509056df1113fc1ca07a SHA-1: a2399ee28325cab617b4c90d418cc52d12fa1b16 SHA-256: 16cf52b4683b36c3c69aa9ed4894babfcf4b66e475eaf42ed6f0eae2269b1b1f
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs that point to other PDF files, many hosted on domains associated with link farms and compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or distributing malware. The primary function appears to be redirecting users through a chain of links, potentially for SEO poisoning or to serve malicious payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://crewmak.ru/uplcv?utm_term=how+to+use+streamlabs+obs+for+youtube PDF link annotation
    • http://abwalabamaave.com/uploads/files/jotazonaraf.pdfIn PDF document text
    • https://www.bbmnetlicitacoes.com.br/cms/ckfinder/upload/files/xekizekebobawujesaz.pdfIn PDF document text
    • http://ptaki.info/imgekoprojekty/files/14481399706.pdfIn PDF document text
    • http://coyada.com/up_images/up_images/rawenalawizupizimiziko.pdfIn PDF document text
    • http://airholic.com/UpFiles/WebEditorFiles/file/28453611927.pdfIn PDF document text
    • http://ouhkpthaa.org/userfiles/99598613970.pdfIn PDF document text
    • https://bcm.es/files/galeria/files/31695606126.pdfIn PDF document text
    • http://teplospectr.ru/images/files/53589817470.pdfIn PDF document text
    • https://bostoncake888.com/UserFiles/files/4783938889.pdfIn PDF document text
    • http://mlsy.cz/images/file/files/fadagibikesutosesogep.pdfIn PDF document text
    • https://www.breastcancerfoundation.in/wp-content/plugins/super-forms/uploads/php/files/cc67614ab09b93ce1512a29cd5e53af9/47227550817.pdfIn PDF document text
    • http://www.akutrans.com/wp-content/plugins/formcraft/file-upload/server/content/files/160748f6465409---zodabo.pdfIn PDF document text
    • https://www.lavishlook.se/wp-content/plugins/super-forms/uploads/php/files/745d0776de4379d8098305e683a63d9b/90583300890.pdfIn PDF document text
    • http://china-baby-clothes.com/d/files/76009822523.pdfIn PDF document text
    • http://waypl.pl/upload/File/66737405553.pdfIn PDF document text
    • https://www.kasekimi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074d68557ad5---52267609615.pdfIn PDF document text
    • http://protok.pro/upload/files/vusarurukur.pdfIn PDF document text
    • http://anhbanglaw.com/userfiles/file/85510906482.pdfIn PDF document text
    • https://promocionesnma.com/wp-content/plugins/super-forms/uploads/php/files/a1cce0e9b547e341a2d80d95f3343382/95880243347.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_off0000d71e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD71E 17012 bytes
SHA-256: 6668b1fe67657dfcdf908cf7bb6cd8cc4cb32074cdbf0f58ee01839c1aacac49
font_01_sfnt_off000103c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103C3 10612 bytes
SHA-256: 0fe863eaca390fb69842e01beb108a4fd45e44799b5999b938a83f80aaee05e5
font_02_sfnt_off00011c31.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C31 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1