Malicious PDF — malware analysis report

Static analysis result for SHA-256 84efd3c4d70792e5…

MALICIOUS

PDF

82.9 KB Created: 2021-09-21 00:25:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 71af07f09a98ea715b651ef8b0fab8a2 SHA-1: d50037605541238ca71df1695b5e02a3930683c8 SHA-256: 84efd3c4d70792e5776fd7e5b267467d5423fc7f7ebed1c1ff7163694b3398d1
96 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 or disposable hosting, indicating a link farm designed to redirect users. The ML classifier also flagged this PDF as malicious. While no scripts were extracted, the structure and URL distribution strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8820

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://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1613da3950dde4---57725265929.pdf
    • https://nepalonlineexam.tisaracademy.com/userfiles/files/towaripem.pdf
    • http://flyingkirin.com/uploadfiles/file/040451012223.pdf
    • http://basyapiemlak.com/yukleme_klasoru/userfiles/file/texotofefepejabet.pdf
    • http://compow.net/ckfinder/userfiles/files/2579244213.pdf
    • https://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/13f2bo3okrkukvi43fbi1g59gn/11620481178.pdf
    • https://razredna-nastava.net/files/40585711164.pdf
    • https://www.simplythebestevents.ca/wp-content/plugins/formcraft/file-upload/server/content/files/161351df03b285---gotego.pdf
    • http://it-hair.com/userfiles/79221202715.pdf
    • http://vervesimuhub.com/userfiles/file/jijenigusopujaroza.pdf
    • http://noithatsah.com/webroot/img/files/setezulenekulazuj.pdf
    • https://thingstodobahrain.net/ckfinder/userfiles/files/60179721818.pdf
    • https://sharidendesignasphalt.com/wp-content/plugins/super-forms/uploads/php/files/37e0a7e6126baa03397e5dd34cec6b3d/dituxiruwisepavu.pdf
    • http://abdon.madteam.net/ckfinder/userfiles/files/mobam.pdf
    • https://wholisticvibrations.com/wp-content/plugins/super-forms/uploads/php/files/490a1b34468999d96bd50a929719e5b2/gulolubege.pdf
    • http://chinalabware.ru/d/files/60515608306.pdf
    • http://tachikawa-derma.biz/ckfinder/userfiles/files/43283998907.pdf
    • https://dp-engineers.com/admin/userfiles/file/murarunawokiwu.pdf
    • http://htygroup.com/upload/files/47687764386.pdf
    • http://nakakinpump.kr/fckeditor/upload/file/bozad.pdf
    • http://sanyosushiglendora.com/uploads/files/16416689930.pdf
    • https://www.naabelectric.com/userfiles/files/20708886777.pdf
    • http://master-vin.ru/files/file/nedatumifikezifuwa.pdf
    • https://dongytueduc.com/wp-content/plugins/super-forms/uploads/php/files/f6lol2e9mao088mbk3f4c6svao/85758508195.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=rtk+heisig+pdf
    • 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_off0000d6b2.bin
0dad85c1b1dea10246ba6ab517238476aace3c1a1ce19216e27594ed181f3a7c		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD6B2 25248 bytes
font_01_sfnt_off00011640.bin
03f29cafcc86eb411933c52f5ceab23e8324491664083bf9ae8be9abb7c214fb		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11640 10380 bytes
font_02_sfnt_off00012db6.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12DB6 16792 bytes

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