Malicious PDF — malware analysis report

Static analysis result for SHA-256 81391c36db51f339…

MALICIOUS

PDF

91.7 KB Created: 2021-06-29 04:23:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: cd7d7bc77d875fc1ebae44d2c0e7b260 SHA-1: 5f7e51c31f17719f789a4dfa93333ebe4ebc61bf SHA-256: 81391c36db51f339da4749653945b97ef99b1554c528df240be00acc36d26d51
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS uploads and disposable hosting, indicating a link farm designed to manipulate search engine results or lure users to malicious sites. ClamAV and ML classifiers also flagged the PDF as malicious, supporting its classification as a phishing or SEO spam document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9924

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 http://plncse.hu/php_data/file/51195085760.pdf In PDF document text
    • http://theydeserveastamp.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607ce40864357---disisumuwokavetinir.pdfIn PDF document text
    • https://endoaccessories.com/wp-content/plugins/super-forms/uploads/php/files/186om1uhultn2kngvdv2mj7nhg/dusodem.pdfIn PDF document text
    • https://dodatnojamstvo.com/userfiles/file/10423169432.pdfIn PDF document text
    • http://atdawnwelift.com/userfiles/file/medajulugezenoroji.pdfIn PDF document text
    • http://laweasy.kr/userfiles/file/82502430108.pdfIn PDF document text
    • http://www.orarestauratorisaf.it/wp-content/plugins/formcraft/file-upload/server/content/files/16087c0fd5c621---peruxenireduvagabuniju.pdfIn PDF document text
    • http://www.aportecnica.com/imagenes/editor/file/wixitenibe.pdfIn PDF document text
    • https://www.frankreich-ferien.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1606cbc80265d8---towotilapexuduvirodalog.pdfIn PDF document text
    • https://www.enviedecrire.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a4aad60719b---26136924387.pdfIn PDF document text
    • http://www.kliningstroy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1608c25a1f2bce---64592417245.pdfIn PDF document text
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/9kc1oj4iv09qljt2tvbldhvv45/22089010346.pdfIn PDF document text
    • http://wienbildarchiv.com/upload_files/files/4791054876.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a8346aba2dd---35278303845.pdfIn PDF document text
    • https://givemeit.ru/wp-content/plugins/super-forms/uploads/php/files/c91e6cc5a72d38ad3e29d152ed4dfbc9/37310076231.pdfIn PDF document text
    • https://www.darrellstuckey.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1f006edfe9---gikuxofijinatejavixemerav.pdfIn PDF document text
    • http://asbufestival.com/uploads/FCK_files/file/44756293006.pdfIn PDF document text
    • https://singaporenotarypublic.com/wp-content/plugins/super-forms/uploads/php/files/5ab242a76c0b1e11fb7bf1f91c1334ca/lexagileg.pdfIn PDF document text
    • https://greenturtleproductions.com.au/wp-content/plugins/super-forms/uploads/php/files/5e22cc6a2054310ce7a7a4caaf377966/sorijapufogejusagit.pdfIn PDF document text
    • http://ebslang.net/_UploadFile/Images/file/860998599.pdfIn PDF document text
    • http://www.veronicaneal.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/160706ff0725c4---48302318465.pdfIn PDF document text
    • https://terravistahometeam.com/wp-content/plugins/super-forms/uploads/php/files/8759e2b29f9d63107d51c929c780cb74/nenilemowodiva.pdfIn PDF document text
    • http://lirealestatelitigator.com/wp-content/plugins/super-forms/uploads/php/files/4cbd4119396c6478f155a96ca7a4f7cc/17117656897.pdfIn PDF document text
    • https://centrosteadycam.it/wp-content/plugins/super-forms/uploads/php/files/2da982c2392f88e541dfd220839902c0/tevaviponujew.pdfIn PDF document text
    • https://bakwanudang.com/contents//files/87944172421.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=bright+house+networks+remote+control+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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ead2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAD2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000102e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102E9 11008 bytes
SHA-256: 9b32f92d87826104bcfc09eb02775f4d80cc441746a78d969eb99d752037bfd7
font_02_sfnt_off00011c69.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C69 16704 bytes
SHA-256: f3a20dd5e700ae390a0fe49f1c8ffa79b3fb96a0bd172bb38c6ac14fcf60674b
font_03_sfnt_off000132fe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x132FE 17708 bytes
SHA-256: 0ab3e7e063e1c4f918df19193415d4ffbbcc6a0404c15c212dd348be9c51bffb