Malicious PDF — malware analysis report

Static analysis result for SHA-256 f73903dcbcf1e1f3…

MALICIOUS

PDF

88.6 KB Created: 2021-07-31 15:12:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: d4e78add214cc2f9d9e592ad332e9fa5 SHA-1: d0f6d74a26885e9c09c07e0c978bdd66564ad10e SHA-256: f73903dcbcf1e1f31631caa42841545e3c16e7b1c7902404c777f2760288296f
96 Risk Score

Malware Insights

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

The ML classifier strongly indicated maliciousness, supported by heuristics identifying the PDF as a link farm pointing to compromised WordPress upload storage and disposable hosting. The document body is heavily obfuscated, preventing analysis of specific lures, but the presence of numerous external URLs suggests an attempt to redirect the user to malicious sites. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9979

Heuristics 5

  • 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://nangluongvada.com/uploads/files/wulekajopoxuwaxive.pdf In PDF document text
    • http://festivaldeliteraturadepereira.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bada5ecc907---33688767959.pdfIn PDF document text
    • http://milcontabil.com.br/wp-content/plugins/super-forms/uploads/php/files/g8ohljs7tmc01uir7gthmtsqi3/65552532013.pdfIn PDF document text
    • https://www.mixedclass.com.au/wp-content/plugins/super-forms/uploads/php/files/50sn1qa29e1qt8fh7fgi5jtq1r/29937331731.pdfIn PDF document text
    • http://hndgyl.com/v15/Upload/file/20216111250529891.pdfIn PDF document text
    • http://eduomania.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088823c6f409---59765023883.pdfIn PDF document text
    • https://gyandeepjkss.org/userfiles/file/zizapifelix.pdfIn PDF document text
    • http://altinay-law.com/images/file/dunezifinawododuxug.pdfIn PDF document text
    • https://adreshosting.com/calisma2/files/uploads/27132036480.pdfIn PDF document text
    • http://2015.letnifestiwal.pl/ckfinder/userfiles/files/nixokexawi.pdfIn PDF document text
    • https://lashmakerpro.it/wp-content/plugins/super-forms/uploads/php/files/e5c63n2390v0cbimkjaogi8hi7/libuzuweg.pdfIn PDF document text
    • http://brandnewgoods.net/userfiles/file/wadidoxi.pdfIn PDF document text
    • https://santechnikosdarbai.lt/images/files/76430411983.pdfIn PDF document text
    • https://omomediacion.com/wp-content/plugins/super-forms/uploads/php/files/63de98c693c3dc7d4d46d3f45ab4ea56/85936742465.pdfIn PDF document text
    • http://caffepontoni.com/uploads/file/tixotukopegovikuxa.pdfIn PDF document text
    • https://sipare.com.ar/wp-content/plugins/super-forms/uploads/php/files/n9lsquba4r818d2qns39rsghsi/48482499879.pdfIn PDF document text
    • https://saraelv.no/wp-content/plugins/formcraft/file-upload/server/content/files/1606f5ec79da67---pebedovosumijaxasiwavip.pdfIn PDF document text
    • https://choiceenergynetwork.com/wp-content/plugins/super-forms/uploads/php/files/d5fa339ae09378118b7b337665ac680d/31809575904.pdfIn PDF document text
    • https://www.temsilcisitesi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094d07c224dc---59745456859.pdfIn PDF document text
    • http://www.pattyn360.com/upload/forum/files/bupezimogatofitewuk.pdfIn PDF document text
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/71399114077bae011523c7a7540b42e3/31580985984.pdfIn PDF document text
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1608303ba0e676---lejokagovezonopure.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=how+to+fix+a+stalled+enginePDF 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_off0000f94b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF94B 16536 bytes
SHA-256: 8ea7e06190846fb746a1625bfa7eba8b430ad9060419b494dee5f77cacc7c5c5
font_01_sfnt_off0001247b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1247B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013c92.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13C92 10608 bytes
SHA-256: 8c09ff01ebfad7b364b032b3d50036fb59ff2b936ed1f5bd5bec482afd3d6278