Malicious PDF — malware analysis report

Static analysis result for SHA-256 53acdde9dcca31a5…

MALICIOUS

PDF

99.2 KB Created: 2021-07-05 14:46:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 5dd4a25b35f1962ecd9af06cc15120bb SHA-1: a51a5c981f4361a6c82e09a36c042a038948abfe SHA-256: 53acdde9dcca31a51a85973963bda47f82895693b97269b7ebff547b894797aa
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as a link farm, with many URLs pointing to compromised CMS uploads and disposable hosting. The ML classifier and ClamAV also identified it as malicious, specifically a phishing trojan. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://rumahbaruku.com/contents//files/tufukimijumoweg.pdf
    • http://sendedianqi.com/upload_fck/file/2021-6-23/20210623043403865275.pdf
    • http://kemenyseprosiklos.hu/upload/file/xegafunezizuvisojivusew.pdf
    • http://raunlarose.us/wp-content/plugins/formcraft/file-upload/server/content/files/1607f30ea761f9---lajusirixatava.pdf
    • http://eyupsifalibitkiler.com/resimler/files/3371523557.pdf
    • http://china-miyaco.com/img/file/2021627114623.pdf
    • https://arab-hams.com/Ups/files/89881458209.pdf
    • https://provisionsinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b1b64631de3---83253369254.pdf
    • http://langeline.com/ckeditor/upload/files/19185622718.pdf
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f42b218628---78877221573.pdf
    • https://www.movingwithmagna.com/wp-content/plugins/super-forms/uploads/php/files/cc41c790fbbeb6d641d592a46f00de0b/pakupit.pdf
    • https://shared401k.com/wp-content/plugins/super-forms/uploads/php/files/a5e6beb4a99ec5440d9817386bb33d0e/737902276.pdf
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fcdb8d9a66---vusexizaza.pdf
    • http://vegasoft.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160bff2a437ad6---4324256719.pdf
    • https://www.dishdivvy.com/wp-content/plugins/super-forms/uploads/php/files/97643a856a5858be192823b34ca38e76/deluzitawiwobojo.pdf
    • http://noithatdangcap.vn/app/webroot/uploads/files/27104329273.pdf
    • http://hillcountryawningsandsunscreens.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a6c4c1353d---nidetigagilomukum.pdf
    • http://alvasari.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c2d434f341---96387799576.pdf
    • https://www.straightmyteeth.com/wp-content/plugins/super-forms/uploads/php/files/43bf63dbdd9e4804ecb9c464be45eeff/puxenuni.pdf
    • http://bilagroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609da68793fc7---dabusemotakupokitijudes.pdf
    • https://sarujiovalente.com/wp-content/plugins/super-forms/uploads/php/files/kh4r0jt2urfhugdo7lhoa0enna/65830372613.pdf
    • https://dolupin.com/calisma2/files/uploads/taxiwesatobanogitigimugop.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=the+truman+show+box+office
    • 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_off000120ad.bin
b2084c7be65a4f100c9affe72492f605d7c8ac239e34a9cf4c52526df194d64e
pdf-font-stream PDF embedded font (sfnt) at offset 0x120AD 17508 bytes
font_01_sfnt_off00014e86.bin
3864dc3678ec191714c6faa605fb3f9652526801579cf63b65677c26a42924da
pdf-font-stream PDF embedded font (sfnt) at offset 0x14E86 10944 bytes
font_02_sfnt_off000167de.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x167DE 16792 bytes