Malicious PDF — malware analysis report

Static analysis result for SHA-256 591b73825bceceb1…

MALICIOUS

PDF

87.2 KB Created: 2021-08-14 18:44:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 49a057b641fbea6ac733d834a529e467 SHA-1: c8ad3118fc22d69c2e28602cafc901648f3c1611 SHA-256: 591b73825bceceb147b2d24fe44080cd0f6abf98302842129d42f593cc26de5e
96 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to compromised WordPress sites and are structured as a link farm. The ML classifier strongly indicated maliciousness, and the presence of multiple distinct hosts hosting PDF files suggests an attempt to distribute malicious content or redirect users to phishing sites. The document body is heavily obfuscated and unreadable, providing no direct clues to its specific purpose beyond the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

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://estigotours.com/wp-content/plugins/super-forms/uploads/php/files/b53cc7bcb6ae17b17937ea184d75f470/sefefibotamipodufezaxulo.pdf In PDF document text
    • http://lpsa.cz/userfiles/file/17174284305.pdfIn PDF document text
    • https://wholisticvibrations.com/wp-content/plugins/super-forms/uploads/php/files/e1b62bd31565fdd3253a621810810758/85784007747.pdfIn PDF document text
    • https://roadtoring.com/wp-content/plugins/super-forms/uploads/php/files/247d0a0a7f7be80e3374c0fb2e82dee1/vadefawada.pdfIn PDF document text
    • https://refundsrefunds.com/wp-content/plugins/formcraft/file-upload/server/content/files/160fbd6216899a---30075380766.pdfIn PDF document text
    • https://netshopnepal.com/userfiles/file/funasoga.pdfIn PDF document text
    • http://adams-gold.ru/archive/image/file/rokesenoluxed.pdfIn PDF document text
    • http://altadirezione-consulting.it/userfiles/files/54594482596.pdfIn PDF document text
    • http://gatewayhotelbangkok.com/upfile_hotel/files/topizavekogobexu.pdfIn PDF document text
    • https://malashealthcare.com/userfiles/files/pekifelove.pdfIn PDF document text
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/5998a6ba358a51a361a9d9b7de268308/gumusaturixepisiven.pdfIn PDF document text
    • https://www.higher-energy-trampolineclub.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c924b3c5581---31781516774.pdfIn PDF document text
    • http://arcomproltd.com/userfiles/file/nalagabebatumulile.pdfIn PDF document text
    • http://systemsbiology.at/uploads/assets/file/matosafav.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/160b5996593a51---raregatulijifonigemekexud.pdfIn PDF document text
    • https://www.auditek.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160b3cbd4320ab---84917944046.pdfIn PDF document text
    • https://adsbudget.net/userfiles/file/60689662603.pdfIn PDF document text
    • https://mama-light.net/business_school/uploads/file/kokadirikubisejini.pdfIn PDF document text
    • https://fundreamz.com/ckfinder/userfiles/files/vujudiw.pdfIn PDF document text
    • http://www.sensible-seeds-premium.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b4010170287---wikat.pdfIn PDF document text
    • https://xn--80aaa1anac6cg.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/dcc8d90673f69a67c5df08aea30831f2/52208612193.pdfIn PDF document text
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/90d35047b64c4b79a770588c2732bbd9/66513549198.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=windows+10+activator+txt+2020+msguidesPDF 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_off0000ee85.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE85 17000 bytes
SHA-256: 9f18772b0745f494db81dd7ccdd3eba94fe2914a48a1eac8c6b1bd43572b0cde
font_01_sfnt_off00011b3e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B3E 11308 bytes
SHA-256: 919409deb49eab03d677030e627a1264b98e03f302268c0eb93d44408ba07600
font_02_sfnt_off000135d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x135D3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1