Malicious PDF — malware analysis report

Static analysis result for SHA-256 55e890dc101d1cf4…

MALICIOUS

PDF

87.4 KB Created: 2021-06-26 03:41:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8c6d915576d50d5d1c4917986189e45c SHA-1: 1fca5895f1812bc75f47c2ddc1101ae1aa828327 SHA-256: 55e890dc101d1cf4137b74481ccd753c35fb1651768a87953b1d8cc9a163ab18
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1055 Process Injection

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous links pointing to compromised CMS uploads and disposable hosting, suggesting a link farm used for phishing or malware distribution. The PDF structure itself does not contain readable content, but the presence of external links is the primary indicator of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e44159fb84---dukuxagipidifu.pdf
    • https://www.dynasil.com/wp-content/plugins/super-forms/uploads/php/files/0d9cbbc39c12a486ca501bd49460be19/topake.pdf
    • https://www.dyna-tech.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16076112deac34---50142626092.pdf
    • https://pankalconstructora.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607dbb6a59ff3---25328500793.pdf
    • http://argentum.com/wp-content/plugins/super-forms/uploads/php/files/fn4e6u56og16daehjel1jbedm2/98748446976.pdf
    • https://baconbites.com/wp-content/plugins/super-forms/uploads/php/files/0nk25j9hnukbj7ba3g2crrmof2/zediwariwesitexekok.pdf
    • http://nutrisoilvietnam.com/upload/files/bobevaninagafewodomibaf.pdf
    • http://www.pilonidalsinus.gen.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1606c8f21d1090---logulawabozefogegiruvubaw.pdf
    • http://slp61.com/clients/e/e2/e296dcecfd7d10ffef0cc83fef253c72/File/2446458052.pdf
    • https://vate-tire.ru/wp-content/plugins/super-forms/uploads/php/files/ccab3183d8b3f0cdbc1e2c23a9f65cf3/zemininuwifesofekiz.pdf
    • https://prtl.pl/userfiles/file/rupumo.pdf
    • https://ncfouting.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090f177069b1---26787951841.pdf
    • https://assignmentmart.com/ckfinder/userfiles/files/18416132197.pdf
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607918349a062---59719618413.pdf
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607e25a4c47ab---17859637490.pdf
    • https://www.cukoyem.com.tr/wp-content/plugins/super-forms/uploads/php/files/opcos5bnnv6ogar33vv7tv7n80/42893075822.pdf
    • https://www.sblending.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607b3e620ef3f---93888986205.pdf
    • http://hchs1972.com/clients/2/2c/2cb73362227bcfbd3ed6ae01b5b3dc46/File/sikerowafimirukuge.pdf
    • http://schooldistrictservices.com/clients/f/f6/f6ab1571d2cdf5e569af7b76e288b17c/File/31573826872.pdf
    • https://profbuhotchet.ru/wp-content/plugins/super-forms/uploads/php/files/1f87489875351b9853116666fa795368/jegesuvaf.pdf
    • https://hocngoaingu123.com/upload/files/31685300001.pdf
    • http://bettaletroom.com/file_media/file_image/file/12495607747.pdf
    • http://www.dean-cpa.com/files/adminpic/file/91088480880.pdf
    • http://brenna-ski.pl/userfiles/file/sonufesubap.pdf
    • http://english-island.pl/wp-content/plugins/super-forms/uploads/php/files/fart8v4lv4rj166s35v1akrud6/1921530114.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=ratched+theme+song
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f35d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF35D 16792 bytes
font_01_sfnt_off00010b74.bin
73314967891f6bf1fc9ce32b2a84c9f38135f02d792cd4a7ed224f7b4d939503
pdf-font-stream PDF embedded font (sfnt) at offset 0x10B74 10624 bytes
font_02_sfnt_off00012368.bin
0f5a1b90967d04671468c972b1bc120246de8fccb7c0579853454d3f9330dbd1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12368 17396 bytes