Malicious PDF — malware analysis report

Static analysis result for SHA-256 4bf9c61349feea7b…

MALICIOUS

PDF

78.8 KB Created: 2021-09-03 18:30:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 63ef85c386f9364d2377b510ec21672b SHA-1: 30f5bc0c7d5e08b425fbb99d9d3babc8df4f9d40 SHA-256: 4bf9c61349feea7bdf100533bb18e7fdb2741415ab8820e637ae49aeb1ed32a6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous external URIs and link farms pointing to potentially compromised websites, suggesting an attempt to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this. While no scripts were explicitly extracted, the nature of the URLs and the detection as a phishing trojan indicate a likely phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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://laborke.ru/uplcv?utm_term=hydrological+cycle+of+water+pdf PDF link annotation
    • http://www.tiande-global.com/ckfinder/userfiles/files/derijafi.pdfIn PDF document text
    • https://chungcungoaigiao.net/uploads/files/zuxapavusaxizibopibox.pdfIn PDF document text
    • http://gelateriacool.it/userfiles/files/raruvonarogetiwikavo.pdfIn PDF document text
    • http://www.bewegeninarnhem.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16086efffae4f7---zazigajajegefusizavi.pdfIn PDF document text
    • http://thietbikhachsanvinhhung1.com/upload/files/9967338111.pdfIn PDF document text
    • https://na-nule.ru/wp-content/plugins/super-forms/uploads/php/files/us7jtkojguf95falefl7se7gi7/52068181839.pdfIn PDF document text
    • https://turismo-galicia.es/ckfinder/userfiles/files/75881232018.pdfIn PDF document text
    • http://www.aadhar-interior.com/userfiles/file/59150004520.pdfIn PDF document text
    • https://altsovmun.ru/userfiles/file/vusiniwabimovujokimojit.pdfIn PDF document text
    • https://mangonebike.com/uploads/file/miwevi.pdfIn PDF document text
    • https://jbdclothiers.net/emailer/userfiles/file/82673243905.pdfIn PDF document text
    • http://abc-tel.ru/data/File/66653874907.pdfIn PDF document text
    • https://www.litesourcenc.com/wp-content/plugins/super-forms/uploads/php/files/b7e71125f897e49527756f0f2f49faa2/4220863090.pdfIn PDF document text
    • http://chalappuram.com/userfiles/file/36576044229.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/8f341861a55473f4d5a884024891db34/xewizitoruruziwuze.pdfIn PDF document text
    • https://www.albispanaderia.com/wp-content/plugins/super-forms/uploads/php/files/421128df950618266095a7c8e1e3132b/25148284627.pdfIn PDF document text
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/16096e011d2d7c---xuzupesazefoje.pdfIn PDF document text
    • http://velocimapper.com//webfiles/file/gojowarumuku.pdfIn PDF document text
    • https://juhaszautovill.hu/userfiles/file/72541496781.pdfIn PDF document text
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/a59a1e0b09f6e9027cd871d9940a19d0/98980741085.pdfIn PDF document text
    • http://debden.org/userfiles/file/balan.pdfIn PDF document text
    • https://censcakmu.org/board/file/files/1738750150.pdfIn PDF document text
    • https://lapdonline.org/file/manulolo.pdfIn PDF document text
    • https://sharpspringwww.kinsta.cloud/wp-content/plugins/super-forms/uploads/php/files/ff67fcd473bdfea4d0cb38fb3388f9eb/fefilumilivuzam.pdfIn PDF document text
    • http://lovewhereyoulv.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/8a16e6f1a486a96e0fede023103877f9/rezawatadozon.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_off0000d36e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD36E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000eb85.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB85 10712 bytes
SHA-256: 240969b3ab8109ed38bd67a05c6bfb9aed557d21d8b1c6999faa924502249128
font_02_sfnt_off0001040d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1040D 16272 bytes
SHA-256: bafff86991f219eddfe499abd473764694f5f8a67eca781f6be0f52ddcc1568b