Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8de8a5702130d8b…

MALICIOUS

PDF

81.3 KB Created: 2021-09-13 18:15:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 0c220ccb987775216f080d209731532e SHA-1: 8cd745e0c79c5e21bf674fe6c3146cc9e670c84d SHA-256: a8de8a5702130d8bb7ad8c14c9e7cb82aa28f69be1a9fcc9986cbb36e0941682
156 Risk Score

Malware Insights

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

The PDF file contains a link farm with numerous URLs pointing to various websites, many of which are hosted on compromised or disposable domains. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware distribution through these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://manhremhoangvan.com/wp-content/uploads/files/27300554506.pdf
    • https://o2opr.co/userfiles/files/8709335159.pdf
    • http://boxethai38.com/upload/file/57517655552.pdf
    • http://tolaniprojects.com/userfiles/file/tegawujiniwividelor.pdf
    • http://xn----ftbkdcamitb5h.xn--p1acf/files/fck/file/lifuvedusatutukapu.pdf
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612e9bec11223---40521085466.pdf
    • https://oncallanatomist.org/ckfinder/userfiles/files/38430321979.pdf
    • http://dongbanja.com/userData/ebizro_board/file/81518222026.pdf
    • http://orosweb.hu/ckfinder/userfiles/files/78511491977.pdf
    • https://watertorens.nl/userfiles/file/mafebosomonukevegeza.pdf
    • https://stl-log.com/htdocs/cljr/data/files/4019591987.pdf
    • http://boki.hu/editor_up/biveke.pdf
    • http://covina.crazyrockinsushi.com/uploads/files/29313022676.pdf
    • http://cukiernia-waltar.pl/qcms/userfiles/file/36066118654.pdf
    • https://thesmithgrouphouston.com/wp-content/plugins/super-forms/uploads/php/files/6f8f43cd34c3e4c93ff2a2f5de88bf4b/jumurizuxinumumisadide.pdf
    • http://wsospice.org/uploads/userfiles/file/file/89856599180.pdf
    • http://swapnakoodu.com/fck_uploads/file/lelem.pdf
    • http://waycreon.net/bhaskar/yii/upload/files/gumejasazezoka.pdf
    • http://qdjshg.com/files/file/88024486409.pdf
    • https://precisionautoandac.com/wp-content/plugins/super-forms/uploads/php/files/bc7e38d9d4afa1af13c3c11f0e469e69/nenokokepojir.pdf
    • http://espokebar.com/uploads/files/23474906230.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=debug+gpu+overdraw
    • 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_off0000dd75.bin
102eabff5645fd531a29c2052982fae04d40ca3fbbedb09e085ef2a427295c24		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDD75 16636 bytes
font_01_sfnt_off0001083a.bin
26eb0c4387b76e1c1a6eb7f9acc92509e7fa47d716dc59823d54c7cc71fce84c		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1083A 10452 bytes
font_02_sfnt_off00011faf.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11FAF 16792 bytes

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