Malicious PDF — malware analysis report

Static analysis result for SHA-256 fea57f9b2c9e9d8f…

MALICIOUS

PDF

93.3 KB Created: 2020-08-29 18:25:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: dabe363fe7fade727b0c19e31b945be1 SHA-1: bc2feb2ea42c956665f0a1536da659c47949240a SHA-256: fea57f9b2c9e9d8f9bd40c3dc6debbfff97e9fab2c5d6d3b13e8fb0616ef1f3c
152 Risk Score

Malware Insights

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

The PDF was flagged as malicious due to a critical heuristic identifying it as a redirector link to known malicious infrastructure. It also contains a mass external PDF link farm, with the primary redirect URL being `https://ttraff.link/wix?keyword=free+toefl+practice+test+quora`. The document body, though heavily obfuscated, contains this same URL, reinforcing its role as a lure. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://ttraff.link/wix?keyword=free+toefl+practice+test+quora
    • https://static.usrfiles.com/ugd/98857b_76edd000ee9e4acbb9f5c2eabd0d14ac.pdf
    • https://static.usrfiles.com/ugd/b8c837_6690fb169f5d4519ae7e6e9a55f3cb58.pdf
    • https://static.usrfiles.com/ugd/33a2e4_d5463eb518c7443895dd9de7c19cea15.pdf
    • https://static.usrfiles.com/ugd/b8c837_6e14e57d5b084f45bf420dce094d6a1d.pdf
    • https://static.usrfiles.com/ugd/b8c837_e3e5f537821d40e59e50b0c2fc822bbe.pdf
    • https://cdn.shopify.com/s/files/1/0430/3680/3233/files/72371156802.pdf
    • https://cdn.shopify.com/s/files/1/0435/3998/8648/files/edit_text_color.pdf
    • https://cdn.shopify.com/s/files/1/0440/6866/7542/files/espn_nhl_standings.pdf
    • https://cdn.shopify.com/s/files/1/0435/6289/3471/files/volimizi.pdf
    • https://cdn.shopify.com/s/files/1/0457/6211/7788/files/muwetazalizibezazenigab.pdf
    • https://cdn.shopify.com/s/files/1/0431/9051/7911/files/place_preposition_exercise.pdf
    • https://cdn.shopify.com/s/files/1/0428/7276/6631/files/vugixepozibuwoteputafoxun.pdf
    • https://cdn.shopify.com/s/files/1/0429/8578/3447/files/saxovaxavebofonosize.pdf
    • https://cdn.shopify.com/s/files/1/0431/0332/2269/files/tajufusiritimarisojok.pdf
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/76588695657.pdf
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/57727452667.pdf
    • 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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012f9b.bin
9e2ace61b8d614355c5974a01b7c1ff55b2fd674d688bdc720361d108ad10467
pdf-font-stream PDF embedded font (sfnt) at offset 0x12F9B 5092 bytes
font_01_sfnt_off00014104.bin
6a2d595162c744deb2bbafab76def4c5bedc9f8e78c66caae8e21c08800ba7c2
pdf-font-stream PDF embedded font (sfnt) at offset 0x14104 11356 bytes